Abstract:
An support rack system, which may be electrically conductive, has one or more generally horizontal crossbars. Each crossbar has a front face and a spaced-apart rear face. Each of the crossbar faces is interconnected at one or more spaced-apart locations to reveal at least one pocket. The crossbar faces are matingly connected adjacent at least one of the pockets. The mating connection of the crossbars has at least one aperture penetrating therethrough. The rack system also has one or more generally parallel, vertically oriented support bars. At least one of the support bars bears a mechanism adapted to attach said crossbars to said support bar with one or more of the crossbar aperture or the crossbar pocket.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to racks for supporting workpieces in industrial coating operations and more particularly to a rack design that permits numerous modes of assembly. 
     Industrial coating systems employ a conveyor from which workpieces are hung on support racks and are conveyed through several stations, usually including stations for performing the steps of cleaning, rinsing, drying, coating, and baking, often including repeats of these steps and often in a different order. In many industrial coating operations, the workpieces travel through an electrostatic coating booth wherein the electrically grounded workpieces are sprayed or coated with electrically charged coating particulates, either liquid or powder. After coating and baking, the coated workpieces are removed from the racks and the racks are reused for another coating cycle. Because of the recycling of the racks, they become coated and encrusted with multiple layers of the coating material. It is important in those instances where electrostatic coating is employed that the support rack be electrically conductive so that workpieces can be maintained in a grounded state. The workpieces are electrically connected to ground through a conductive support rack so that electrically charged particulates are attracted to the workpieces by the electrostatic field. 
     During each coating cycle, a layer of coating is applied to all exposed electrically conductive surfaces, including the support rack. Unless identical workpieces are coating during each coating cycle, the support racks need to be disassembled for cleaning and reassembly for the next workpiece to be coated. Thus, flexibility in support rack assembly, disassembly, and reassembly is a desired feature. 
     Heretofore a variety of support rack assemblies have been proposed in the art. U.S. Pat. No. 6,189,709 proposes an electrically conductive rack, which has a crossbar attached to the vertical beams using the open Z-folded end, including a threaded rod and nut assembly (FIG.  4 ), an S-hook (FIG.  5 ), vertical wires inserted in an aperture (FIG.  6 ); and a flat tongue (FIG.  7 ). U.S. Pat. No. 5,908,120 proposes to attach a vertical rod to the crossbar via an aperture that penetrates vertically through the crossbar. U.S. Pat. No. 5,897,709 proposes to attach an upper horizontal crimped area of the crossbar with a hole to vertical J-hooks that serve as the vertical rod. U.S. Pat. No. 5,531,334 proposes to attach the flat end of the crossbar to the vertical rod with a threaded fastener or rivet (FIG.  7 ). U.S. Pat. No. 5,524,774 proposes to use holes in the vertical rod to engage elongate hooks for supporting the crossbar. U.S. Pat. No. 5,147,050 proposes to use holes in the vertical rod and spaced-apart fingers of a bracket to support the crossbar. U.S. Pat. No. 5,020,677 proposes to rest the crossbar on supporting fingers extending from the vertical bars wherein spring clips or the like retain the crossbar on the fingers. U.S. Pat. No. 4,899,966 shows an integral crossbar and vertical bar assembly (FIG.  5 ). U.S. Pat. No. 4,628,859 shows a coat hanger for hanging parts from. U.S. Pat. No. 4,097,359 shows a rectangular bar assembly where the upper and lower crossbars and attached to the left and right vertical bars by “welding, bolting, etc.” U.S. Pat. No. 4,097,359 proposes a rectangular bar assembly where the supporting hooks are inserted into U-shaped horizontal bars. U.S. Pat. No. 5,762,205 proposes to hang the horizontal crossbars to vertical channel beams with hooks that protrude from the beams and which fit into the U-shaped crossbars. U.S. Pat. No. 4,037,727 proposes a vertical bar that fits through vertically oriented apertures in the crossbars wherein a thumbscrew holds the bar in position. 
     It is to a rack assembly with unique design for assembly by a diverse number of mechanisms that the present invention is directed. 
     BRIEF SUMMARY OF THE INVENTION 
     An support rack system, which may be made electrically conductive, has one or more generally horizontal crossbars. Each crossbar has a front face and a spaced-apart rear face. Each of the crossbar faces is interconnected at one or more spaced-apart locations to reveal at least one pocket. The crossbar faces are matingly connected adjacent at least one of the pockets. The mating connection of the crossbars has at least one aperture penetrating therethrough. The rack system also has one or more generally parallel, vertically oriented support bars. At least one of the support bars bears a mechanism adapted to attach said crossbars to said support bar with one or more of the crossbar aperture or the crossbar pocket. 
     Another aspect of the present invention is a method for assembling a support rack system. This method commences with providing one or more generally horizontal crossbars. Each crossbar has a front face and a spaced-apart rear face. Each of the faces are interconnected at one or more spaced-apart points to reveal pockets between the points. The faces are conformingly pinched together adjacent to at least one of the pockets. The pinch has at least one aperture penetrating therethrough. One or more generally parallel, vertically oriented support bars also are provided. At least one of the support bars bears a mechanism adapted to attach the crossbars to the support bar using one or more of the crossbar aperture or the crossbar pocket. Finally, one or more crossbars are attached to the one or more support bars with the mechanism attached to one or more of the crossbar aperture or the crossbar pocket. 
     A further aspect of the present invention is a method for industrial coating of workpieces hung from support racks which racks are affixed to a conveyor. The first step is to provide the support rack system. Then a workpiece is hung from at least one of the crossbars. The rack system is hung from a conveyor. Finally, the workpiece is subjected to industrial coating, e.g., electrostatic powder coating, oil coating, latex coating. 
     Advantages of the present invention include a rack system design that is easy to assemble. Another advantage is a rack system that can be manufactured to be easily disassembled. A further advantage is a rack system that can be assembled using a variety of mechanisms. Yet another advantage is a rack system that can be configured into a variety of patterns. These and other advantages will be readily apparent to those skilled in this art based upon the disclosure set forth herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature and advantages of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which: 
     FIG. 1 is a front perspective view of the electrically conductive support rack system showing five different mechanisms for assembly; 
     FIG. 2 is a side elevational view of the support rack system of claim  1 ; 
     FIG. 3 is a bottom view of one of the horizontal crossbars of the support rack system of claim  1 ; 
     FIG. 4 is a cross-sectional view taken along line  4 — 4  of FIG. 1; 
     FIG. 5 is a cross-sectional view taken along line  5 — 5  of FIG. 1; 
     FIG. 6 is a cross-sectional view taken along line  6 — 6  of FIG. 1; 
     FIG. 7 is a cross-sectional view taken along line  7 — 7  of FIG. 1; 
     FIG. 8 is a cross-sectional view taken along line  8 — 8  of FIG. 1; and 
     FIG. 9 is a front perspective view of an alternative embodiment of the electrically conductive support rack system. 
     The drawings will be described in more detail below. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     On occasion, the user may want the support rack, which may be electrically conductive, (or “support rack”) assembled permanently. On occasion, the user may want to be able to disassemble the support rack for cleaning and reassembly. On other occasions, the user may want to be able to disassemble the support rack and reassemble it in a different configuration. The inventive support rack provides the user with all of these features. 
     Referring initially to FIG. 1, electrically conductive support rack,  10 , is seen to include a pair of spaced-apart, generally vertically oriented, side support bars,  12  and  14 , each of which have an upper hook section,  16  and  18 , respectively, for attachment, for example, to an overhead conveyor (not shown). Other modes of attachment of support rack  10 , of course, are well known in the art and/or can be conceived. Side support bars  12  and  14  are shown to be generally flat (see FIG.  2 ), but can be of other cross-sectional configuration, as can be appreciated by the skilled artisan. 
     Side support bars  12  and  14  carry therebetween generally horizontal, crossbars,  20 ,  22 ,  24 ,  26 ,  28 , and  30 . Each of these crossbars is seen to carry workpieces,  32 ,  34 ,  36 ,  38 ,  40 , and  42 , respectively. A spring clip, known as a gravity hook in the industry,  44 ,  46 ,  48 ,  50 ,  52 , and  54 , respectively, carries each workpiece. Each spring clip is inserted between pockets formed in each crossbar, such as is illustrated in FIG.  3 . Crossbar  20  is representative of the other crossbars shown in FIG.  1 . It will be seen that crossbar  20  is formed from a pair of generally parallel faces, a front face,  56 , and a spaced-apart rear face,  58 . The faces are interconnected at spaced-apart junctions or dimples, such as junctions,  60  and  62 , which are representative of all such junctions. Disposed between junctions  60  and  62  is a pocket,  64 . The spring clips, such as spring clip  44  fits into these pockets and is retained thereby. Other means of attaching clips or gravity hooks to the crossbars for holding workpieces are known in the art and can be envisioned by the skilled artisan. 
     Of importance for present purposes is the end,  66 , of crossbar  20 . End  66  has been pinched to form an integral segment and an adjacent pocket,  68 . End segment  66  also contains at least one hole or aperture, for example a pair of holes,  70  and  72 , as shown in FIG. 8 (see also FIGS. 1,  4 ,  5 ,  6 , and  7 ). End segment  66  optionally may be welded also, such as a central weld,  71 . Crossbar  20 , and indeed the other crossbars shown in FIG. 1 as well, are attached to vertical bars  16  and  18  using the apertures in end segment  66  and adjacent pocket  68 . Such attachment can be permanent or can be temporary for quick disassembly of support rack  10 . Pinched end  66  also prohibits coating medium from entering the crossbars from the sides (or ends); thus, keeping the inside clear of buildup that would be detrimental to good electrical contact. 
     Six different modes of attachment of the crossbars to the vertical support bars are illustrated in the drawings for illustration purposes, as the skilled artisan may conceive of additional modes of attachment. With respect to crossbar  20 , reference is made to FIG. 4 whereat one of the ends,  74 , having a pair of vertically-oriented apertures is used to secure crossbar  20  to vertical support bar  12  using threaded bolts,  76  and  78 , held by nuts,  80  and  82 , respectively. In this mode of attachment, crossbar  20  can be removed merely by unscrewing nuts  80  and  82 , and removing threaded bolts  76  and  78 . Of course vertical support bar  12  also has a pair of apertures for insertion of threaded bolts  76  and  78  therethrough. 
     A second mode of attachment is illustrated in FIG. 5, wherein an end,  84 , of crossbar  22  has a pair of vertically-oriented apertures that mate with corresponding apertures in vertical support bar  12 . Rivets,  86  and  88 , are inserted through these apertures to secure cross bar  22  to vertical support bar  12 . This rivet mode of attachment is more permanent than threaded bolts and nuts, though it can be removed with effort. 
     A third mode of attachment is illustrated in FIG. 6, wherein an end,  90  of crossbar  24  has been spot welded to vertical support bar  12  with a pair of spot welds,  92  and  94 . Any suitable welding means can be used. Such welding mode of attachment is even more permanent than the first two modes described above. 
     A fourth mode of attachment is illustrated in FIG. 7, wherein and end,  96 , of crossbar  26  has a pair of apertures (again, like apertures  70  and  72 ) as does vertical support bar  12 . A U-shaped clip,  98 , is placed through the apertures in vertical support bar  12  to reveal a pair of ends through which the apertures in end  96  are inserted for carrying crossbar  26 . Clip  98  could be permanently attached to vertical support bar  12  or could be removably attached to vertical support bar  12 . In this mode of attachment crossbar  26  can be removed readily. If more than one crossbar were hung with such clips, different length clips could space the crossbars different distances from the vertical bars. Again, the flexibility of the inventive rack is illustrated. 
     A fifth mode of attachment is illustrated in FIG. 8, wherein a L-shaped clip,  100 , is welded to vertical support bar  12  by a spot weld,  102 . The upper leg of clip  100  is inserted into the pocket formed between an end,  104 , and a dimple,  106 . whereat the front and back sections of crossbar  28  are joined. Similar pockets are formed between all of the dimples. The end pocket, however, is particularly useful in securing the crossbars to the vertical support bars. This drawing also shows how spring clip  52  is retained between a pair of dimples,  108  and  110 , for carrying workpiece  40 . A conventional C-clip,  51 , also is seen carrying a workpiece,  41 . Each of the dimples have a central core of physical contact between the faces of the crossbars, which core can support various conventional or special designed clips for supporting a variety of workpieces. 
     A sixth mode of attachment relies of the apertures in the ends of the crossbars, such as aperture  72  of end  104  of crossbar  28 . In FIG. 1, a gravity hook,  112 , having bent ends is inserted through lower aperture  72  of crossbar  28  and an upper aperture in an end,  114 , of crossbar  30 . A similar gravity hook,  116 , arrangement is seen on the other end of crossbars  28  and  30  for crossbar  28  to carry crossbar  30 . 
     Finally, while a pair of vertical support bars have been illustrated in the drawings, it will be readily apparent that one or more vertical support bars could be used. In other configurations where the crossbars are not supported at the ends of the crossbars, the crossbars still desirably are pinched or otherwise closed to prevent unwanted penetration of coating material. FIG. 9 illustrates an alternative embodiment of the electrically conductive support rack. In particular, a rack,  118 , is seen to be constructed from a single vertical support bar,  120 , from which crossbars,  122 ,  124 ,  126 ,  128  and  130 , are hung. In this regard, the ends of each crossbar are closed (e.g., closed ends  132  and  134  of crossbar  122 ) to prevent infiltration of coating, e.g., powder coating, during coating operations. Vertical support bar  120  is supported by a rack assembly,  136 , which is composed of a horizontal member,  138 , which is supported by J-hook members,  140  and  142 . Other configurations for rack assembly  136  can be envisioned by the artisan and can be used to support the novel rack assembly, as those skilled in the art will appreciate. 
     Crossbar  122  is shown affixed to vertical support bar  120  by screws, as described for crossbar  20  in FIG.  1 . Crossbar  124  is shown affixed to vertical support bar  120  by pop rivets, as described for crossbar  22  in FIG.  1 . Crossbar  126  is shown affixed to vertical support bar  120  by welds, as described for crossbar  26  in FIG.  1 . Crossbar  128  is shown affixed to vertical support bar  120  by U-clips, as described for crossbar  28  in FIG.  1 . Finally, crossbar  130  is shown carried by crossbar  128  using clips  112  and  116 , as described for crossbar  30  in FIG.  1 . 
     In order for such modes of attachment to be utilized in for support rack  118 , a central section of each crossbar is pinched flat and provided with holes or apertures, similar to end  66  in FIG.  3 . It will be appreciated that one or more vertical support bars can be used in constructing the novel electrically conductive support rack, again adding to the flexibility of its design. A workpiece,  144 , is seen suspended from crossbar  122  via a clip,  146 . A workpiece,  148 , is seen suspended from crossbar  124  via a clip,  150 . These workpieces are not the same size and weight. The novel support rack, again, is flexible in design for handling such different sized and weighted workpieces. Alternatively, added weight can be added to one or more crossbars to balance the support rack, if necessary, desirable, or convenient. 
     While the invention has been described with reference to a preferred embodiment, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. In this application all units are in the metric system and all amounts and percentages are by weight, unless otherwise expressly indicated. Also, all citations referred herein are expressly incorporated herein by reference.