Abstract:
An apparatus and method for cleaning fabrication equipment, such as for example wire feed tips provided on welding guns. Equipment of that nature usually includes an outlet through which joining or filling material is dispensed and which may easily become blocked by weld splatter or the like when in such close proximity to the work piece being fabricated. The apparatus provides a support means for holding the equipment, cleaning means for removing debris from the equipment, and control means for effecting relative movement of the support means and cleaning means in a swift and efficient manner.

Description:
CLAIM FOR PRIORITY 
     This application is a U.S. national phase entry under 35 U.S.C. §371 from PCT International Application No. PCT/BR2012/1000401, filed Sep. 28, 2012, which claims benefit of priorty of Great Britain Patent Application No. 1116920.8 filed Sep. 30, 2011, the subject matter of both of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a method and apparatus for cleaning a wire feed tip used in fabrication processes and more particularly to a method and apparatus for cleaning the interior of the wire feed tip. 
     BACKGROUND 
     The wire feed tips to which the present disclosure relates are those used in fabrication processes such as welding and, to a lesser extent brazing and soldering. Such processes usually employ a filler or joining material, typically in the form of a consumable metal wire that may be held within the wire feed tip and directed towards the work pieces to be joined. Since those wire feed tips are most commonly used in welding processes, such as for example gas metal arc welding (GMAW), the following description will relate specifically to welding, though it should be borne in mind that the present disclosure is in no way limited to such processes. 
     Briefly, unlike brazing and soldering, welding requires the surfaces of the work pieces to be melted and a filler material to be introduced to create a molten pool of material that may eventually cool to form a solid joint. The surfaces of the work pieces may be melted by the heat generated from a flame, an electric arc, laser or several other energy sources. 
     Referring again to GMAW, this technique uses an electric arc to generate heat and usually employs a welding gun connected to a spool of wire and a supply of inert gas. The welding gun includes the wire feed tip (also known as a welding tip) which may be an elongate unit made from copper (or other suitable material) and has a bore extending therethrough to accommodate the wire from the spool. Wire feed tips are commonly available in a range of sizes and styles so as to suit the size of the wire to be dispensed therefrom, which typically has a diameter in the range of 0.7 mm to 2.4 mm and for some applications as large as 4 mm. Further, the means by which the wire feed tip connects to the gun may also vary, but quite commonly it comprises a threaded portion at the rear which engages a threaded opening on the welding gun. The welding gun also includes a gas nozzle adjacent the wire feed tip and a welding shield that surrounds the gas nozzle and the wire feed tip so as to direct the gas towards the end of the wire and thus the work piece being welded. 
     Occasionally and particularly when the welding gun is too closely positioned to the work piece, weld splatter may adhere to the wire feed tip or the end of the wire may become so hot that it welds itself to the wire feed tip. These scenarios are particularly problematic since they may restrict or even prevent wire being dispensed from the wire feed tip. To address these problems, it is common to remove the welding shield and detach the wire feed tip from the welding gun so that it may be replaced or refurbished. Refurbishment usually includes grinding the end of the tip so as to remove the portion coated in weld splatter and thus reveal a new end with a clean bore. This process obviously reduces the length of the tip so can be carried out only a limited number of times before the tip becomes unusable. 
     It is a principal object of the present disclosure to overcome the problems outlined above. 
     SUMMARY OF THE DISCLOSURE 
     According to a first aspect of the disclosure, there is provided an apparatus for cleaning a wire feed tip having a bore extending therethrough, the apparatus comprising: support means adapted to hold the wire feed tip so that the bore is substantially coaxial with a first axis; a cleaning member having a cleaning portion, said cleaning portion being sized to locate within the bore of the wire feed tip and having an axis arranged coaxially with the first axis; and a control member drivingly coupled to one of the support means and the cleaning member and operable to effect relative translational movement of said support means and said cleaning member. 
     According to a second aspect of the disclosure, there is provided a method of cleaning a wire feed tip having a bore, the method comprising the steps of: providing an apparatus having wire feed tip support means, a cleaning member, and control means operable to effect relative translational movement of the wire feed tip support means and the cleaning member; securing the wire feed tip on the wire feed tip support means; and operating the control means so as to cause translational movement of the wire feed tip support means and the cleaning member, such that a portion of the cleaning means extends through the bore of the wire feed tip to dislodge any debris. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a wire feed tip for attachment to a welding gun; 
         FIG. 2  is a perspective view of a cleaning apparatus arranged in its retracted position; 
         FIG. 3  is a perspective view corresponding to  FIG. 2 , but with the cover of the cleaning apparatus removed; 
         FIG. 4  is a perspective view of the cleaning apparatus of  FIGS. 2 and 3  arranged in its extended position and with a wire feed tip attached; 
         FIG. 5  is a perspective view corresponding to  FIG. 4 , but with the cover of the cleaning apparatus removed; 
         FIG. 6  is a side view of the cleaning apparatus in its retracted position with the cover removed and the wire feed tip attached; and 
         FIG. 7  is a side view corresponding to  FIG. 6 , but arranged in its extended configuration. 
     
    
    
     DETAILED DESCRIPTION 
     The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described therein and illustrated in the Figures are intended to teach the principles of the present disclosure, enabling those of ordinary skill in the art to implement and use the present disclosure in different environments and for many different processes. Therefore, the exemplary embodiments are not intended to be, and should not be considered as, a limiting description of the scope of patent protection. Rather, the scope of patent protection shall be defined by the appended claims. 
       FIG. 1  shows a wire feed tip  10  attachable to a welding gun (not shown) and arranged to direct welding wire (not shown) to the work piece (not shown) being welded. Such wire feed tips  10  may take many different shapes and sizes according to the welding gun to which they are to attach and the size of the welding wire to be dispensed. Generally, however, they are all tubular in nature and include an inlet at their rear end and an outlet at their front end. This particular wire feed tip  10  has a frusto-conical front portion  11 , a cylindrical mid portion  12 , a diametrically smaller rear portion  13  provided with an external thread  14 , and a bore  17  extending through its centre. The end  15  of the frusto-conical front portion  11  is partially closed, but provided with a small exit hole  16  associated with the bore  17  and through which the welding wire is dispensed. 
     Referring now to  FIGS. 2 to 7 , there is shown a cleaning apparatus, generally indicated  20 , for cleaning the bore  17  of the wire feed tip  10 . The cleaning apparatus  20  may include a base  21  having a cleaning unit  22  and a support unit  23 . 
     The base  21  may be generally planar and may have a substantially flat lower surface  25  which may be mounted to a work bench (not shown) and may be secured in place by bolts or other suitable fasteners (not shown). In an alternative embodiment, the base  21  may also be furnished with one or more legs (not shown) for elevating the cleaning apparatus  20  above ground level. The base  21  may be made from metal, plastics or other suitably stiff material to provide sufficient rigidity. 
     The support unit  23  may comprise a pillar  26  upstanding from the base  21  and possibly spaced from the cleaning unit  22 . The pillar  26  may be integral to the base  21  or attached by fasteners, adhesive or other known suitable means (not shown). The pillar  26  may take any suitable shape, but in the exemplified embodiment it is generally rectangular in that it includes opposed side faces  27 , a top face  28 , a front face  29  and a rear face  30 , which is proximal to the cleaning unit  22 . The pillar  26  may have a receptacle  33  to which the wire feed tip  10  may be attached and which may comprise an opening extending through the front and rear faces  29 , 30  for receiving the rear portion  13  of the wire feed tip  10 . To secure the wire feed tip  10  in position, the opening may be threaded for engagement with the external thread  14  of the wire feed tip  10 . In a more basic arrangement, the opening may be sized to allow the rear portion  13  to pass therethrough and the wire feed tip  10  may be secured in place by a nut (not shown) presented to the rear face  30  for engagement with the external thread  14 . 
     Referring again to the exemplified embodiment, the receptacle  33  may be furnished with a circular insert  35  that may have a circumferential outer face (not shown) provided with threads for engagement with threads formed within the receptacle. Additionally or alternatively, the insert may be clamped in the required position by a grub screw  36 , or like fastener, extending through the top face  28  of the pillar  26  and engaging the insert  35 . The insert  35  may define an annular wall  37  adapted to extend forward of the front face  29  and a circular land  38  disposed within the annular wall  37 , and arranged possibly concentrically thereto. The annular wall  37  and the circular land  38  may define an annular recess  39  in which the rear portion  13  of the wire feed tip  10  may locate and the internal face of the annular wall  37  may be threaded to engage the external threads  14  provided on the wire feed tip  10 . The circular land  38  may be provided with a through hole  41  for receiving a needle  65  associated with the cleaning unit  22  to be discussed in more detail below. The insert  35  may be interchangeable to accommodate wire feed tips  10  of different sizes. 
     The cleaning unit  22  may comprise a cleaning body  45  upstanding from the base  21  and a control member  46  pivoted to the cleaning body  45 . The cleaning body  45  may be integral to the base  21  or may be attached to the base  21  by known suitable means, for example, by welding, adhering or fastening. For instance, the cleaning body  45  may be attached to the base  21  by screws (not shown) passing through the lower face (not shown) of the base  21  and into a lower face (not shown) of the body  45 . In this embodiment the cleaning body  45  is generally cuboidal and as such has opposed side faces  47 , an upper face  48 , a lower face (not shown), a first end  49  proximal to the support unit  23  and a second end  50  distal to the support unit  23 . 
     The cleaning body  45  may be provided with a channel (not shown) for receiving a cleaning member  55 . The channel may be substantially linear and may be formed such that its longitudinal axis L extends through the cleaning unit  22 , the support unit  23  and the space therebetween. The channel may have a first open end  57  defined in the first end  49  and a second open end (not shown) defined in the second end  50 . In one embodiment the second open end of the channel may be closed so as to serve as an end stop for the cleaning member  55  located therein. The channel may have a substantially circular cross-section, though alternative shapes are possible. A slot  58  may be formed in each side face  47  of the cleaning body  45  and arranged in communication with the channel. Furthermore, the slots  58  may be the same size and may be located at corresponding positions on their respective side faces  47 . 
     The cleaning member  55  may have a cross-section selected so as to locate within and slide along the channel. The cross-section of the cleaning member  55  may be selected so as to correspond substantially to the cross-section of the channel and form a close running fit therewith. The cleaning member  55  may include a first end  61  proximal to the first open end  57  of the channel, a second end  62  proximal to the second end of the channel and a peripheral surface  63  extending between the two ends. 
     The first end  61  of the cleaning member  55  may be furnished with an elongate cleaning tool, in the form of a needle  65  arranged to extend coaxially to the longitudinal axis L. The needle  65  may be arranged to locate within and clean debris from the bore  17  of the wire feed tip  10  and therefore the size and shape of the needle  65  may be selected according to the size and shape of the wire feed tip  10  to be cleaned. In order for the needle  65  to withstand the forces to which it may be subject when urged into the bore  17  of the wire feed tip  10 , it may be reasonably rigid and robust and possibly made from steel or another suitable material exhibiting those characteristics. The needle  65  may also be provided with an abrasive finish to assist with the removal of debris. The length of the needle  65  may vary, but may be at least as long as the bore  17  so that the free end of the needle  65  reaches the small exit hole  16  of the wire feed tip  10 . Indeed, the needle  65  may need to be significantly longer than the bore  17  if the cleaning member  55  does not extend to the support unit  23  in its fully extended position, to be discussed below. 
     The needle  65  may be integral to the cleaning member  55  or detachably mounted thereto. A detachable needle  65  may be easily replaced by an identical needle when damaged or by a different size needle when a different size wire feed tip  10  requires cleaning. In the embodiment shown in  FIGS. 2 to 7 , the cleaning member  55  is furnished with a cap  68  disposed over the first end  61  and the needle  65  extends concentrically from the centre of the cap  68 . The first end  61  may be diametrically smaller than the remainder of the cleaning member  55  in order to receive the cap  68 , which may have an external diameter substantially equal to that of the remainder of the cleaning member  55 . The cap  68  may be secured to the first end  61  by grub screws  69 , adhesive or other suitable means. 
     The control member  46  may comprise any suitable means for effecting translational movement of the cleaning member  55  in a reciprocating manner. In the present embodiment shown in the drawings it comprises a lever pivoted to the cleaning body  45  and coupled to the cleaning member  55 . The lever includes an arm  70  having a lower end furnished with a fork  71  defining two limbs  72  that straddle the cleaning body  45 . The free ends of the limbs  72  may be provided with coaxial holes (not shown) that receive a pivot pin  73  arranged to extend through a pivot bore (not shown) formed in the cleaning body  45 . The ends of the pivot pin  73  may be threaded to receive nuts  74  to restrict inadvertent removal of the control member  46  from the cleaning body  45 . 
     The limbs  72  may be provided with apertures  75  which may be of a similar size and may be arranged in corresponding positions along the length of the limbs  72 . The apertures  75  may be elongate and may extend radially along the limbs relative to the pivot axis P, such that a portion of each aperture  75  may lie in registration with a portion of a respective slot  58  formed in an adjacent side face  47  of the cleaning body  45 , at least for a predefined range of pivot angles of the control member  46 . The control member  46  may be drivingly coupled to the cleaning member  55 . For example, projections (not shown) may extend from opposed sides of said cleaning member  55 , through adjacent slots  58  in the side faces  47  of the cleaning body  45  and finally through the apertures  75  in the limbs  72  of the fork  71 . The projections may have threaded ends (not shown) that may be furnished with nuts  77  or like captive devices. In the present embodiment, a bore (not shown) is formed through the cleaning member  55  and a pin (not shown) extends through that bore such that its ends emerge from diametrically opposed locations on the cleaning member  55  before passing through the slots  58  in the side faces  47  and the apertures  75  in the limbs  72 . The ends of the pin define the projections, and at least the very ends of which may be provided with a thread for engaging the nuts  77 . 
     The cleaning apparatus  20  may also be furnished with a detachable cover  80  which may be mounted to the cleaning body  45  and the pillar  26  to conceal the space therebetween, or more particularly, the moving parts, such as the cleaning member  55  located in that space. The cover  80  may take many suitable forms, but in this embodiment it comprises a U-shape channel having a central portion  81  and two sides  82 . The U-shape channel may be inverted such that the central portion  81  may rest on the top face  48 ,  28  of the cleaning body  45  and the pillar  26 , while the sides  82  depend downwardly so as to be fastened to the side faces  47 , 27  of the cleaning body  45  and the pillar  26  by screws  84 . 
     In an alternative embodiment not shown, the control member  46  may be adapted to effect translational movement and rotational movement of the cleaning member  55 . This might be achieved by dividing the cleaning member  55  into a translational portion and a rotational portion arranged end to end. The translational portion may be located in the channel and may be coupled to the control member  46  in the above described manner. The rotational portion may have one end coupled to the adjacent end of the translational portion so as to allow relative rotational movement of those portions while not allowing relative translational movement of those portions. The other end of the rotational portion may be provided with the needle  65  in the same manner as described above. A helical groove may be formed in the circumferential face of the rotational portion and a projection may be provided in the channel so as to locate within the groove. 
     Thus as the control member is driven towards its extended position, the translational portion and therefore the rotational portion are driven along the channel towards the support unit  23 . However, as the rotational portion starts to move along the channel, the projection rides along the helical groove so as to cause the rotational portion also to rotate. Since the needle  65  is fixed to the rotational portion, it too rotates as it moves through the bore of the wire feed tip  10 . 
     INDUSTRIAL APPLICABILITY 
     Prior to use, the size of the needle  65  should be checked to ensure it corresponds to the size of the bore  17  of the wire feed tip  10  to be cleaned. If necessary the needle  65  should be replaced, which first requires the cover  80  to be removed by releasing the screws  84  and lifting the cover  80  upwardly above the cleaning unit  22  and the support unit  23  until the sides  82  are free. The needle  65  may then be accessed to enable the grub screws  69  to be released and the cap  68  urged towards the support unit  23  while restricting forward movement of the control member  46 . A different needle  65  may then be attached by locating the cap  68  over the first end  61  of the main portion  60  and then tightening the grub screws  69 . The cover  80  may then be replaced. 
     It may also be necessary to replace the insert  35  in the event that the needle  65  does not fit within the through hole  41  or the wire feed tip  10  does not fit within the annular recess  39 . The insert  35  may be replaced by releasing the grub screw  36  and subsequently twisting the insert  35  counter-clockwise. The replacement insert  35  may then be presented to the opening and then twisted clockwise until the threads fully engage, before finally tightening the grub screw  36 . 
     The wire feed tip  10  may then be fitted to the cleaning apparatus  20  by locating the rear portion  13  into the annular recess  39  and then twisting the wire feed tip  10  in the clockwise direction to enable the external threads  14  to engage fully with those formed on the internal face of the annular wall  37 . 
     To clean the bore  17  of the wire feed tip  10  supported in the insert  35 , the arm  70  should be arranged in its retracted position whereat the pin through the cleaning member  55  is at the end of the slot  58  proximal to the second end  50  of the cleaning body  45 . Thence, the arm may be pivoted forward until the pin reaches the end of the slots  58  proximal to the first end  49  of the cleaning body  45 , which in turn drives the cleaning member  55  forward toward the support unit  23 . As the cleaning member  55  is driven forward, the needle  65  enters the bore  17  of the wire feed tip  10  and dislodges any debris set therewithin. If significant resistance occurs, it may be necessary to pivot the arm  70  alternately between the retracted and the extended positions so as to drive the needle  65  reciprocatively along the bore  17 . This may also be necessary to remove any previously dislodged debris from the bore  17 .