Abstract:
A design is disclosed for promoting the formation of weld between a first member and a second member whereby a fin is introduced at the outer corner portion of the first member to minimize the creation of defects such as runout or rollover. While such a design is applicable to any industrial welding operation, this design is of particular interest for welding bases or bit blocks holding cutting bits onto rotatable drums, wheels or chains used in construction or mining operations.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a design to promote welding in corner regions and more particular to the use of a fin extending outwardly from an outside corner region to promote the proper formation of a weld around such a corner region.  
           [0003]    2. Description of the Related Art  
           [0004]    Welding is defined as the process of uniting two members by heating them until they are molten and fused, with or without the use of a filler material.  
           [0005]    The focus of this application will be directed to welding utilizing a filler material to join two parts which intersect at a corner and for which weld filler must be used to produce a continuous weld around the corner.  
           [0006]    Manual welding typically is labor intense and requires a high level of skill on behalf of the welder to efficiently produce a strong high quality weld. Because there are frequently great demands for production placed upon a welder, there is always a desire to improve efficiency by either improving the manner in which the weld is laid or by providing a design which requires less weld material. A design which may permit both of these beneficial features is highly desirable.  
           [0007]    Welding material around the corner of a workpiece presents unique problems to which the subject invention is directed. As an example, FIG. 1, which is prior art, illustrates a system by which a first member  10  is secured to a second member  15  by a weld  20 . The first member  10  has at least a first side  25  and a second side  30 . Each side has an upper portion  32  and a lower portion  34  wherein the lower portion  34  is chamfered relative to the upper portion  32 . The weld  20  is fused to the lower portion  34  of at least the first side  25  and the second side  30  of the first member  10 . The weld  20  is additionally fused to the surface  35  of the second member  15  thereby securing the first member  10  to the second member  15 .  
           [0008]    Although defects associated with welding may occur along any portion of the weld  20 , the outside corner portions of welds seem to more frequently have defects. The first member  10  which is illustrated as a solid piece, has only outside corners  36 ,  37 ,  38 ,  39 . To put this in perspective, if the first member  10  was hollowed out to form a cavity having a perimeter of the same shape as the exterior of the first member  10 , the enclosed corners would be referred to as inside corners.  
           [0009]    [0009]FIG. 2 illustrates a section view of the corner portion of the weld along arrows “ 2 - 2 ” in FIG. 1. The lower portion  34  of the side  25  is not illustrated in either this view or the view to be discussed with FIG. 3. In FIG. 2, the bottom face  40  of the first member  10  contacts the surface  35  of the second member  15 . Weld  20  is used to attach the first member  10  to the second member  15 . The metal filler of the weld  20  penetrates the side  25  of the first member  10  and simultaneously penetrates the surface  35  of the second member  15 . However, it is not uncommon when welding a corner region to produce a defect known as a rollover, which is also called an overlap. Such a defect is associated with fillet welds and can be produced when either the current of an arc welding machine is too low to properly fuse the second member  15  or the travel speed for the welding process is too low to accept the amount of metal filler being deposited. As a result, a portion of the weld  20  merely flows onto an area of surface  35  and does not fuse with the surface  35 . The rollover portion, which is indicated by  50  must be removed to ensure the integrity of the weld  20 . Such a defect must be removed by grinding, which requires additional time and labor.  
           [0010]    Another type of weld defect which is not uncommon in corner regions is illustrated in FIG. 3 and is referred to as an undercut. FIG. 3 is a view similar to FIG. 2 illustrating a different defect. An undercut is an irregular gouge which is generally found in the upper toe of a horizontal fillet weld. With reference to FIG. 3, the first member  10  has a bottom face  40  which contacts the surface  35  of the second member  15 . However, in this situation, the weld  20  droops from a recess or undercut  55  produced in the side  25  of the first member  10 . The side  25  of the first member  10  has been melted but has not been refilled with weld material. Most often this defect is caused by improper selected welding conditions such as the electrode angle, travel speed and welding current. It is more likely to occur when attempting to make fillet welds with legs that are more than 0.3 inches in length. Just as a with a rollover defect however, such defects are unacceptable if the integrity of the weld is to be maintained and such defects must be removed. These defects in welds on outside corners may be avoided but only at the cost of a significant increase in welding time and expense.  
           [0011]    U.S. Pat. No. 3,832,523 discloses a method for electrical arc welding. In FIG. 12 of that patent, a segment  50  is illustrated which is used on a vertical section for preventing a resulting weld bead which is not completely solidified from drooping. Segment  50  acts as a physical barrier to the weld material. As a result, the section on the plates under segment  50  will not be covered with weld material and therefore the weld will not be continuous. Furthermore, the weld does not extend around a corner and many applications require a continuous bead of weld material around a corner.  
           [0012]    U.S. Pat. No. 4,208,563 illustrates a welding method using a break away flux dam in which copper wires are used to surround the weld area and create a pool of molten weld metal with a top layer of flux. While this illustrates a manner of containing a weld, it once again does not address a weld around a corner with a continuous bead of weld material.  
           [0013]    A design is needed which permits a welder to secure a first member, which may be metal, having outside corners to a second member, which also may be metal, while applying a continuous weld around the corners of the member in an expedient fashion that will provide a weld with integrity and minimize the potential for producing defects such as rollover and undercut while also reducing the time and cost of welding.  
           [0014]    While such a design is applicable to welding any two members with outside corners, it is of particular significance in securing a bit block or base to a rotatable member, such as a drum, wheel or chain, for equipment used in construction operations, such as road planning or trenching, or in mining operations, such as coal mining.  
         BRIEF SUMMARY OF THE INVENTION  
         [0015]    One embodiment of the invention is directed to a first member for welding to a second member wherein the first member is comprised of a body having a top, a bottom and a face on the bottom for contacting a surface on the second member. The first member has a plurality of sides between the top and the bottom including a first side adjacent to the face, and a second side adjacent to the face. The first side and the second side converge to define an outside corner region between the top and the bottom. A fin extends from the corner region to promote the formation of a weld in the corner region.  
           [0016]    A second embodiment of the invention is directed to a system which includes the first member just described mounted upon a second member using weld material.  
           [0017]    A third embodiment of the invention is directed toward one application of the first member as a metal block for mounting upon a metal drum used in mining or construction operations.  
           [0018]    A fourth embodiment of the invention is directed toward one application of a system including the first member as a metal block mounted to a metal drum and secured with weld material for use in mining or construction operations.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is prior art and illustrates a perspective view of a first member secured to a second member with a weld;  
         [0020]    [0020]FIG. 2 is prior art and illustrates a cross-sectional view along arrows “ 2 - 2 ” in FIG. 1 highlighting a weld defect;  
         [0021]    [0021]FIG. 3 is prior art and illustrates a view similar to FIG. 2 highlighting a different weld defect;  
         [0022]    [0022]FIG. 4 is a perspective view of a first member to be secured to a second member by welding and incorporating a design in accordance with the subject invention;  
         [0023]    [0023]FIG. 5A illustrates a top view of the arrangement in FIG. 4 in which the first member has radiussed corners;  
         [0024]    [0024]FIG. 5B illustrates a variation of the view in FIG. 5A in which the first member has square corners;  
         [0025]    [0025]FIG. 6 is a cross-sectional view of a corner illustrated by arrows “ 6 - 6 ” in FIG. 4 in accordance with the subject invention;  
         [0026]    [0026]FIGS. 6A, 6B,  6 C and  6 D are cross-sectional views similar to FIG. 6 but showing different embodiments of the subject invention;  
         [0027]    [0027]FIG. 7 is a portion of the plan view illustrated along arrows “ 7 - 7 ” illustrated in FIG. 4;  
         [0028]    [0028]FIGS. 7A and 7B are plan views showing different embodiments of the design illustrated in FIG. 7;  
         [0029]    [0029]FIG. 8 is a perspective view illustrating a first member attached to a second member having fins extending from within the first member;  
         [0030]    [0030]FIG. 9 is a sectional view of the corner region along arrows “ 9 - 9 ” in FIG. 8;  
         [0031]    [0031]FIG. 10 is a bottom view of the first member illustrated in FIG. 8;  
         [0032]    [0032]FIG. 11 illustrates a perspective view of a first member which is a base incorporating the subject invention and secured to the surface of a second member, which is a rotatable member, used for mining or construction operations;  
         [0033]    [0033]FIG. 12 is a bottom view of the base illustrated in FIG. 11;  
         [0034]    [0034]FIG. 13 illustrates a perspective view of a first member which is a base incorporating another embodiment of the subject invention and secured to the surface of a second member, which is a rotatable member, used for mining or construction operations;  
         [0035]    [0035]FIG. 14 is a side view of the base illustrated in FIG. 13;  
         [0036]    [0036]FIG. 15 is a bottom view of the base illustrated in FIG. 13; and  
         [0037]    [0037]FIG. 16 is a partial section view illustrated along arrows “ 16 - 16 ” in FIG. 14. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]    The subject invention is directed to outwardly extending fins in the outer corner region of a first member secured to a second member by welding. By providing a fin in the body of the weld, the weld material will have additional surface on which to adhere. This additional surface provides support to the weld when in a fluid condition thereby minimizing defects such as rollover or undercut in or near the corner regions.  
         [0039]    Welding which is appropriate to secure the first member to the second member, may be any number of different weld methods including arc welding, gas welding or any other welding method which deposits a filler between two pieces to be joined.  
         [0040]    Additionally, while the subject invention will be illustrated using a single fillet weld on a tee joint, it should be appreciated the subject invention may be useful for many other types of welds including a single level groove, a single J-groove or any other weld type suitable for a tee joint in which an outside corner must be welded.  
         [0041]    [0041]FIG. 4 illustrates a perspective view of a first member  110  attached to a second member  115  on the surface  117  of the second member  115 . The first member  110  has a body  112  and a top  120  and a bottom  122  with a bottom face  125  and a plurality of sides  130 ,  135 ,  140  and  145  and outside corners  150 ,  155 ,  160 ,  165  between the top  120  and bottom  122 . While the first member  110  illustrated in FIG. 4 has four sides  130 ,  135 ,  140  and  145  and four outside corners  150 ,  155 ,  160 ,  165  the subject invention will be directed to only an outside single corner  150  with the understanding that the invention may be applicable to any outside corners including the remaining three illustrated in FIG. 4. For that reason, side  130  will be referred to as the first side  130  and side  135  will be referred to as the second side  135 .  
         [0042]    While the body  112  in FIG. 4 is quadrilateral, attention will be directed to one outside corner and it should be appreciated the subject invention may be applied to a first member  110  having any number of different shapes in so much as any of these shapes has at least one outside corner in which a continuous weld is required.  
         [0043]    The first side  130  and the second side  135  are adjacent to the bottom face  125 . Furthermore, the first side  130  and the second side  135  converge to define an outside corner region highlighted by the dotted line labeled  170  between the top  120  and bottom  122 .  
         [0044]    A fin  175  extends from the outside corner region  170  to promote the formation of a weld (not shown) in the outside corner region  170 . The first side  130  and the second side  135  converge to form a corner angle A which, although shown as approximately 90° in FIG. 4, may actually have a range between 10° to 150°. The first member  110 , second member  115  and fin  175  are all made of materials which are compatible for welding together. As an example, all of the parts may be weld compatible metal. The weld material must also be selected to be compatible with these parts.  
         [0045]    Turning attention to FIG. 5A, the outside corner region  170  is defined with a transition segment  180  connecting the first side  130  with the second side  135 . FIG. 5B illustrates a different arrangement in which there is no transition segment but has a corner region  170  bordered by first side segment  190  and second side segment  195 . Fin  175  is removed from one corner for illustration clarity. The first side  130  has a length L1. The second side  135  has a length of L2. The first side  130  and second side  135  intersect at intersection point  185 . The first side segment  190  extends from the intersection point  185  back along the first side  130  a distance of L1/4 or less. The second side segment  195  extends from the intersection point  185  back along the second side  135  a distance of L2/4 or less.  
         [0046]    Therefore, the corner region  170  may be comprised of the intersection of the first side  130  and second side  135  through a transition segment  180  as illustrated in FIG. 5A or may be comprised of the region proximate to the intersection of the first side  130  and the second side  135 . It should be noted that on FIG. 5A the transition segment  180  is illustrated as a curved segment but that this segment may also be straight.  
         [0047]    [0047]FIG. 6 illustrates the fin  175  as a separate piece attached to the body  112 . Such an attachment may be through a tack weld or other conventional means for attaching. A weld  20  is illustrated in phantom to show the relative position of the weld  20  relative to the fin  175 .  
         [0048]    [0048]FIG. 6A illustrates another embodiment in which the fin  175  is not a separate piece but is an integral part of the body  112  of the first member  110  which can be formed when the body  112  itself is formed by casting or forging or may be subsequently machined or ground into a casted or formed part.  
         [0049]    In still another embodiment, the fin  175  may be an integral part of the body  112  or may be a separate piece attached to the body  112  but, in either case as illustrated in FIGS. 6B and 6C, the fin  175  may be vertically spaced from the bottom  120  of the body  112 .  
         [0050]    Although the fin  175  has been illustrated as having a triangular configuration, the fin  175  may also have any of a wide variety of polygonal shapes including a quadrilateral shape as illustrated in FIG. 6D.  
         [0051]    Briefly returning to FIG. 4, the fin  175  may have a thickness “t” and a width “W” wherein the thickness t is less than ¼ of the width W of the fin  175  when the width W is the maximum width at any part of the fin  175 .  
         [0052]    Directing attention to FIG. 7, the fin may have two opposing vertical walls  177 ,  179  and a fin line  215  extending between them to form a fin angle B with a line  220  extending along one side  130  of the body  112 . As illustrated in FIG. 7, the fin angle B is approximately 45° however may have a value of between 0-45°.  
         [0053]    As illustrated in FIG. 7A, which is an alternate embodiment of the arrangement in FIG. 7, it is possible to mount the fin  175  upon the surface  117  of the second member  115  adjacent to the body  112  of the first member  110 . The fin  175  may also be spaced a fin distance D from the body  112 . When the fin  175  is spaced from the body  112  of the first member  110 , the length of the fin  175  and fin distance D must be considered together such that the intended weld will completely enclose the area of the fin  175 .  
         [0054]    As previously discussed in conjunction with FIG. 7, the fin  175  may be oriented along the line  215  through the fin  175  to form the fin angle between 0°-45° with a line extending along the firs side  130 . FIG. 7B illustrates such an arrangement in which the fin angle B is 0°.  
         [0055]    So far each embodiment of the subject invention has illustrated the fin  175  extending outwardly from the outermost perimeter of the body  112 . However, it is possible for the underside of the member to have a chamfer and the fin  175  to be recessed within the chamfer such that it extends outwardly from within the body  112 .  
         [0056]    [0056]FIG. 8 illustrates a perspective view of a first member  310  having a body  312  mounted to a second member  315  by weld material (not shown). The second member  315  has a surface  317 . The body  312  has a top  320  and a bottom  322  including a bottom face  325  which rests against the surface  317  of the second member  315 . The base has sides  330 ,  335 ,  340 ,  345  with associated corners  350 ,  355 ,  360 ,  365 .  
         [0057]    Just as before, the body  312  may have any number of a variety of different shapes and for purposes of describing the subject invention, side  330  will be referred to as the first side  330  and side  335  as the second side  335  which meet to define an outside corner region  370  similar to that described in previous embodiments.  
         [0058]    The embodiment illustrated in FIG. 8 is different from previous embodiments in that, as illustrated in FIG. 9, which is a section view along arrows “ 9 - 9 ” in FIG. 8, the side  330  is comprised of an upper portion  332  and a lower portion  334  which is chamfered inwardly from an upper portion  342 . The chamfer on the lower portion  334  creates a cavity  372  beneath the perimeter of the body  312  which permits a greater amount of weld material to be used in securing the first member  310  to the surface  317  and the second member  315 . A fin  375  may be positioned proximate to the chamfer on the lower portion  334  in the corner region  370  to promote the formation of a weld  321 .  
         [0059]    [0059]FIG. 10 illustrates a bottom view of the first member  310  in FIG. 8 and shows the bottom  322  with the bottom face  325  and the lower portion  334  extending from the sides  330 ,  335 ,  340  and  345  to define the chamfer on the lower portion  334 .  
         [0060]    What has so far been described is a first member secured to a second member utilizing outwardly extending fins to promote the formation of a weld. It should be understood that such a design can be applied to a wide number of designs in which one piece is welded to another piece and in which it is necessary to have weld material around an outside corner associated with these pieces.  
         [0061]    While many practical applications for this invention may be found, one particular application is illustrated in FIGS.  11 - 12  in which a base  410  holding a bit block  411  with a cutting bit (not shown), wherein the base  410  is secured to the surface  417  of a rotatable member  415 , such as a rotatable drum, used in mining or construction operations. A similar arrangement without fins is disclosed in U.S. Pat. No. 4,542,943 which is hereby incorporated by reference. In the present design, both the base  410  and rotatable drum  415  are metal. The base  410  has fins  475  similar to those discussed previously with FIGS.  8 - 10 . For illustrative purposes, base  410  is shown without weld material securing the base  410  to the rotatable drum  415  while base  410 ′ is shown with weld material  419  securing the base  410 ′ to the rotatable drum  415 . One or more bases  410  may be secured to the rotatable drum  415  in this manner. One hundred or more bases may be welded upon larger rotatable drums  415 .  
         [0062]    Throughout this application reference will be made to a base welded to a rotatable drum for mining or construction operations. The invention should not be limited to this embodiment. While frequently the base is welded directly to the rotatable drum and a bit block is secured within the base, the bit block itself may be welded directly to the rotatable drum and in this arrangement the bit block actually performs as a base. For that reason, the term “base” is intended to cover both the base when it is welded directly to the drum or the bit block when it is welded directly to the drum.  
         [0063]    Furthermore, the base or bit block may be welded to another rotatable member other than a drum such as a rotatable wheel or chain. However, for purposes of this discussion, reference will be made to a base welded to a rotatable drum with the understanding that such terminology is not intended to be limiting.  
         [0064]    [0064]FIG. 12 illustrates a bottom view of the base  410  in FIG. 11. Specifically, the base  410  has a body  412  with a top (not shown) and a bottom  422 . The bottom  422  has a bottom face  425  which contacts the surface  417  of the rotatable drum  415 . The bottom  422  of the body  412  generally follows the contour of the surface  417  of the rotatable drum  415 , which is cylindrical.  
         [0065]    Locating bores  480 ,  485  may be used with mating pins (not shown) to position the base  410  upon the rotatable drum  415 .  
         [0066]    Many of the features in FIG. 12 are identical to those already illustrated in FIG. 10 including first side  430 , second side  435  and sides  440 ,  445  which define outside corners  450 ,  455 ,  460 ,  465 . Sides  430  and  435  intersect to define an outside corner region  470  which includes an outwardly extending fin  475  with similar features as those previously discussed.  
         [0067]    FIGS.  13 - 16  illustrate an embodiment similar to that discussed in FIG. 7B in which at least one fin forms a fin angle B of 0° with a line extending parallel to one of the sides of the base. Specifically, FIG. 13 illustrates a base  510  with a bit block  511  for use in mining or construction operations, wherein the base  510  is secured to a surface  517  of a rotatable drum  515  used in mining or construction operations. The base  510  has fins  575  similar to those discussed previously with FIGS. 11 and 12. For illustrative purposes, the base  510  is shown without weld material securing the base  510  to the rotatable drum  515  while base  510 ′ is shown with weld material  519  securing the base  510 ′ to the rotatable drum  515 .  
         [0068]    [0068]FIG. 14 illustrates a side view of the base  510  illustrated in FIG. 13. The base  510  has a body  512  a top  520  and a bottom  522  with a bottom face  525  which contacts the surface  517  of the rotatable drum  515 . As illustrated in FIG. 15 which shows a bottom view of the body  512  in FIG. 14, the body  512  has four sides  530 ,  535 ,  540 ,  545  and respective corners  550 ,  555 ,  560 ,  565 . Each side may be comprised of an upper portion  532  and a lower portion  534 . In a fashion similar to that discussed with respect to FIGS. 8 and 9, the lower portion  534  of each side may be chamfered such that the fin  575  extends outwardly from this chamfered surface thereby permitting the fin  575  to extend outwardly within the perimeter of the body  512 .  
         [0069]    Locating bores  580 ,  585  may be used with mating pins (not shown) to position the base  510  upon the rotatable drum  515 .  
         [0070]    [0070]FIG. 16 illustrates a section view along arrows “ 16 - 16 ” in FIG. 14 to highlight the upper portion  532  and the lower portion  534  of side  530  in FIG. 14. As illustrated, the fin  575  extends from the lower portion  534 . The fin  575  may terminate at the periphery of the body  512  or, although not shown, may extend beyond the periphery of the body  512 .  
         [0071]    While the base  510  and the rotatable member  515  may be welded in a variety of different ways using different material, one manner of welding the base  510  to the rotatable member  515  is as follows.  
         [0072]    The base  510  may be made of a steel such as AISI 4140, AISI 4340, AISI 8640 or AISI 8740. In the event AISI 8740 steel is used, it may be quenched and tempered to a Rockwell Hardness of between 40-45 RW “C”.  
         [0073]    The rotatable member  515  may be made of AISI 1018 or AISI 1020 steel.  
         [0074]    The weld may be laid with GMAW (Gas Metal Arc Welding) using 7000 series flux core welding wire protected during welding by an inert gas such as carbon dioxide. The welding wire may be, for example, TR70 welding wire available from the Hobart Company or Dual Shield 7100 Ultra welding wire available from the Esap Company or equivalent welding wire from another manufacturer. A GMAW welding machine (MIG) may be used set at between 21-26 volts using {fraction (1/16)} inch weld wire fed at a rate suitable for amperage between 185-285 Amps.  
         [0075]    The weld may also be laid with SMA (Shielded Metal Arc Welding) using stick electrodes available from the Hobart Company as 7018 or 7018-M stick electrodes or equivalent stick electrodes from another manufacturer with a suitable welding machine.  
         [0076]    A typical base would have a side with a length of about 3 inches and a chamfer at the bottom of the side. To lay the weld, two reverse passes are typically required. In the first pass, which is a root pass, an approximate ¼ inch width of weld material is deposited in a single direction between the base and the rotatable member at the bottom of the chamfer. In the second pass, which is the fillet pass, a fillet weld of between ⅝-¾ inches is deposited in the opposite direction with a fillet oscillating pass over the root pass material. While two reverse passes are suitable for many applications, when additional weld material must be laid, additional weld passes are necessary.  
         [0077]    Further included within the subject invention and discussed with respect to FIG. 4, is a method for attaching a first member  110  to a surface  117  of a second member  115  wherein the first member has a top  120  and a bottom  122 . The bottom  122  has a bottom face  125  for contacting the mounting surface  117  of the second member  115 . The first member  110  may have a plurality of sides  130 ,  135 ,  140 ,  145  between the top  120  and the bottom  122 . However, for the purposes of the subject invention only, two adjacent sides are necessary and for that reason, reference will be made to a first side  130  adjacent to the bottom face  125  and a second side  135  adjacent to the face  125 . The first side  130  and the second side  135  converge to define an outside corner region  170  between the top  120  and the bottom  122 .  
         [0078]    The method for attaching the first member  110  to the mounting surface  117  of the second member  115  is comprised of the steps of attaching a fin  175  to the first member so that the fin  175  extends from the corner region  170 . The fin  175  may be attached by tack welding or by any other attachment method which would secure the fin  175  to the first member  110  during a welding operation. The first member  110  is then positioned upon the surface  117  of the second member  115  and welded along at least the first side  130  and second side  135  of the member  110  and along the surface  117  of the second member  115  adjacent to the member in the corner region  170  until the weld material covers the fin  175 .  
         [0079]    By incorporating the design of the present application into metal bases for welding onto rotatable drums used in mining or construction applications, quality welds can be readily made not only at the drum manufacturer but also out in the field. The time required to weld a base has been reduced by approximately ⅓. This produces a significant cost savings when one considers welding large numbers (e.g. 100 or more) of bases onto a drum or the cost of downtime in the field when a drum is being repaired.  
         [0080]    It is thought that the present invention and many of its intended advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts thereof without departing from the spirit and the scope of the invention or sacrificing all of its material advantages, the form herein before described being merely preferred or exemplary embodiments thereof.