Abstract:
A wire feeder for laser welding is provided, comprising a body having a first end and a second end, and a longitudinal passageway extending from the second end to the first end, wherein the passageway is sized to permit passage of a wire therethrough. A wire feeding tube is connected to the first end of the body and in communication with the passageway, and a wire holder is connected to the second end of the body, wherein the wire holder contains a supply of wire. A feeding device is mounted on the body and in communication with the passageway, wherein the feeding device is adapted to urge the wire through the wire feeding tube. The wire feeder may be used for a variety of intricate welding operations, but is particularly suited for laser welding in the jewelry field.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This nonprovisional patent application claims priority under 35 U.S.C. 517 119 to U.S. Provisional Application Ser. No. 61/103,991, filed on Oct. 9, 2008. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not applicable. 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON COMPACT DISC 
       [0004]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0005]    1. Field of the Invention 
         [0006]    The present invention relates to devices used to store and feed a wire for use in laser welding, as well as to methods of manufacturing such devices. 
         [0007]    2. Description of Related Art 
         [0008]    In the field of laser welding, the welding technique requires a small spot size, resulting in small heat-affected zones and high heating and cooling rates. Consequently, there is a need for precise positioning of the welding wire very close to the point where the laser strikes. 
       SUMMARY OF THE INVENTION 
       [0009]    A wire feeder for laser welding is provided, comprising a body having a first end and a second end, and a longitudinal passageway extending from the second end to the first end, wherein the passageway is sized to permit passage of a wire therethrough; a wire feeding tube connected to the first end of the body and in communication with the passageway; a wire holder connected to the second end of the body, wherein the wire holder contains a supply of wire; and a feeding device mounted on the body and in communication with the passageway, wherein the feeding device is adapted to urge the wire through the wire feeding tube. 
         [0010]    Optionally, the feeding device may be operable by a motor, or it may comprise a manually operated roller, wherein a portion of the wire resides between the roller and an opposing member resiliently biased against the roller. The roller may include a textured surface sufficient to grip the portion of the wire when the wire is urged through the feeding tube. 
         [0011]    In a preferred embodiment, the body includes an internal cavity having a conically tapered portion sufficient to guide the wire from the holder into the passageway without compromising the structural integrity of the wire. It is also preferred that the passageway is immediately adjacent to the feeding device as the wire is urged toward the feeding tube by the feeding device. 
         [0012]    The wire stored within the wire holder is preferably between 28 gauge and 36 gauge wire, which is typically used in laser welding applications. The body is optionally color-coded to a specific wire type, and the wire holder includes indicia to identify the wire contained within the wire holder. Preferably, the wire holder is constructed from a material sufficiently transparent to enable a user to ascertain the remaining supply of wire within the wire holder. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements. 
           [0014]      FIG. 1  shows a top view of a wire feeder in accordance with one embodiment of the present invention. 
           [0015]      FIG. 2  shows a perspective exploded view of the embodiment of  FIG. 1 . 
           [0016]      FIG. 3  shows another top view of the embodiment of  FIG. 1 . 
           [0017]      FIG. 4  shows a cross-sectional view of the embodiment of  FIG. 1 . 
           [0018]      FIG. 5  shows a perspective view of the embodiment of  FIG. 1 . 
           [0019]      FIG. 6  shows an alternative embodiment of the invention having a replaceable cartridge. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Before the subject invention is further described, it is to be understood that the invention is not limited to the particular embodiments of the invention described below, as variations of the particular embodiments may be made and still fall within the scope of the appended claims. It is also to be understood that the terminology employed is for the purpose of describing particular embodiments, and is not intended to be limiting. Instead, the scope of the present invention will be established by the appended claims. 
         [0021]    In this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. 
         [0022]      FIGS. 1 and 2  show one exemplary embodiment of a wire feeder  1  used for precise positioning of a welding wire. The welding wire may be of any suitable size, including but not necessarily limited to small gauge wire. The wire feeder  1  may be used for laser welding as well as other types of welding requiring the use of fine wire, typically 28 gauge to 36 gauge wire, such as in jewelry manufacturing and repair. 
         [0023]    In the exemplary embodiment as shown in  FIGS. 1-5 , the wire feeder  1  comprises a body  10  having a first end  2  and a second end  3  with a wire holder mount  12  at the second end  3 . The welding wire  25  may be stored or coiled inside a wire holder  30 , which may be attached to, inserted into, or mounted over the wire holder mount  12  as shown in  FIG. 1 . The wire holder  30  is illustrated in  FIG. 1  only, and is not shown in the remaining figures for clarity. The wire holder  30  may be permanently attached, or removably attached (such as by screwing, or by the use of clips, snaps, or similar fastening techniques) from the body  10  so as to allow for replacement of the welding wire  25  as needed. As seen in  FIG. 4 , an internal cavity  26  is formed within the body  10  and extends from the second end  3  into the interior of the body  10 . The internal cavity  26  ends in a conically tapered portion  27  which is sized and shaped to guide the wire  25  into the passageway  24  without compromising the structural integrity of the wire  25 . In other words, the wire  25  should glide easily across the tapered portion  27  and into the passageway  24  without kinking or breaking the wire  25 . 
         [0024]    In one exemplary embodiment, the wire holder  30  is in the form of a tube formed from plastic or other suitable material, and mounted over the wire holder mount  12 . Preferably, the wire holder  30  is constructed from a material sufficiently transparent to enable a user to visibly ascertain the remaining supply of wire  25  within the wire holder  30 . Also, it is preferred that the wire holder  30  include some form of indicia  31 , such as lettering or numbering, to identify the specific type of wire  25  contained within the wire holder  30 , e.g. the size of the wire  25 , the amount of wire  25 , and the type of metal. During assembly, welding wire  25  is coiled separately and placed inside the wire holder  30 . In one embodiment, the body  10  is approximately 2 to 4 inches in length, and the wire holder  30  is approximately 2 to 4 inches in length. 
         [0025]    Preferably, the welding wire  25  is fed through a longitudinal passageway  24  in the body  10  by turning a feed roller  14  installed into a recess  28  in the body  10 . The recess  28  communicates with the passageway  24 , such that rotation of the feed roller  14  draws the wire  25  from the passageway  24  and urges the wire  25  through the first end  2  of the body  10 . The feed roller  14  is rotatably mounted on the body  10  by an axle  22  inserted through an axle mounting hole  29  formed into the body  10 , best shown in  FIG. 2 . The feed roller  14  preferably includes at least one knurled outer wheel  15  which can be positively turned by the user&#39;s finger, and a smaller inner wheel  16  having serrations or a textured surface to firmly grip the wire  25 . 
         [0026]    When the wire  25  is contacted by the inner serrated wheel  16  of the feed roller  14 , it is important that the wire  25  is adequately supported underneath to prevent the wire  25  from becoming kinked or otherwise undesirably bent inside the body  10 , and to enable the inner wheel  16  to firmly grip the wire  25 . Therefore, in a preferred embodiment best shown in  FIGS. 2 and 4 , a plunger or rod  18  is resiliently biased by a spring  20  against the inner wheel  16  of the feed roller  14 , such that the wire  25  slides against the plunger  18  as it is urged through the passageway  24 . During assembly of the device  1 , the spring  20  is inserted into a spring retaining hole  21  formed into the body  10 , followed by the plunger  18 . The feed roller  14  and axle  22  are then installed as described previously herein. 
         [0027]    A wire feeding tube or needle  4  is connected to the first end  2  of the body  10  and is in communication with the passageway  24 . The wire feeding tube  4  is mounted to the first end  2  by press fitting, adhesive bonding, or any other suitable method that does not obstruct the wire  25  from passing easily from passageway  24  into the wire feeding tube  4 . Optionally, a rubber retaining sleeve  35  may also be employed within a suitable void formed into the body  10 . The wire feeding tube  4  extends from the first end  2  and is employed during welding to guide the wire  25  for precise positioning. The wire feeding tube  4  may be of any suitable length and material, although it would typically be constructed of steel and extend about 5-20 millimeters from the front end  2 . 
         [0028]    Because of the challenges working with fine wire, especially in the range of 28-36 gauge wire, it is easy for such wire to become kinked or bent inside the device  1 , especially as the wire  25  leaves the feed roller  14  and re-enters the passageway  24 . Therefore, to minimize such problems, it is desirable for the passageway  24  to be immediately adjacent to the feed roller  14  as the wire  25  is urged toward the first end  2 . 
         [0029]    In one embodiment, the feed roller  14  may alternatively be turned by a small electric motor placed inside the body  10  to provide motive force at the press of a button or movement of a switch. In one embodiment, the feed roller  14  may be totally enclosed in the body  10  with the motor and power source (such as a battery), with only a button or switch on the surface. 
         [0030]    The body  10  may be of any size and shape suitable for operation by a welder. Specifically, it may be elongated with a three-sided cross-section in part, as shown, or be a cylinder or oval. The feed roller  14  may be on the top, bottom, or side of the body  10  when in use, and multiple feed rollers may be used. The body  10  may be solid, or hollow in whole or in part to reduce weight. It may be made of any suitable material, but preferably of plastic. Conveniently, the body  10  may be constructed in different colors, such that color-coded bodies  10  are used to indicate different types of wire  25 . In one embodiment, the device may be provided as a complete, disposable unit, with wire  25  pre-loaded in a permanently attached wire holder  30 . 
         [0031]    Finally, with reference to  FIG. 6 , an alternative embodiment is depicted wherein the device  1  includes a replaceable cartridge  40 . The cartridge  40  is loaded with a coiled wire  25  as described above, and comprises a transparent tube  42  mounted onto a cartridge base  43 . A cylindrical guide portion  44  extends from the base  43  and includes a conically tapered portion  45  to guide the wire  25  into the cavity  26  of the body  10 . When a new cartridge  40  is desired, a loaded cartridge  40  is inserted into the body  10 , such that the guide portion  44  is snugly received within the cavity  26  of the body  10 . When the cartridge  40  is empty, a new cartridge  40  is simply installed as a replacement, thus keeping the body  10  as a reusable device. 
         [0032]    All references cited in this specification are herein incorporated by reference as though each reference was specifically and individually indicated to be incorporated by reference. The citation of any reference is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such reference by virtue of prior invention. 
         [0033]    It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention set forth in the appended claims. The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.