Abstract:
Brush holder assemblies are detailed. The assemblies may employ rails, rather than boxes, for supporting brushes. They additionally may extend along all, or substantially all, of the lengths of the brushes for enhanced support of the brushes.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61/574,740, filed Aug. 8, 2011, titled “Brush Holder-Rail Support System,” the entire contents of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to brush holders and associated equipment and more particularly, although not necessarily exclusively, to brush holder assemblies having rails for supporting brushes. 
       BACKGROUND OF THE INVENTION 
       [0003]    Commonly-owned U.S. Pat. No. 7,365,470 to Eger, et al., the contents of which are incorporated herein by this reference, describes and illustrates innovative brush holder assemblies. Included as part of such a brush holder may be a brush box designed to support and restrain some movement of a brush during operation of a rotating device such as a commutator or a slip ring. In this sense the brush holder is conventional, as brush boxes generally are commonly used to support brushes. 
         [0004]    Assemblies of the Eger patent have been well-received by users. Further innovations, nevertheless, may continue to improve their functionality, as well as functionality of other brush holders, in some circumstances. For example, brush cooling may be difficult when boxes are used, as the boxes cover much of the surface area of the brushes. Likewise brush maintenance may be difficult because of the surface-area coverage of the boxes. Conversely, because boxes do not typically extend the entire length of brushes (at least when new), they leave portions of the brushes unsupported. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention improves functionality of existing brush holder assemblies. Unlike conventional such assemblies, those of the present invention provide rails, rather than boxes, for supporting brushes. The rails may cover substantially less surface area of brushes than do boxes, promoting cooling when the brushes are in use and facilitating maintenance when they are not in use. The rails additionally may extend along, and thereby support, entire lengths of the brushes. 
         [0006]    Although rails consistent with the present invention may be formed of any suitable material, presently preferred is that they be made of stainless steel because of its strength, abrasion resistance, and resistance to corrosion. Stainless steel additionally has high electrical resistivity (especially as compared to other metals), reducing unintended current flow from the brushes through them to other components. Of course, other electrically-insulating material may be applied or attached to the rails for purposes of further current reduction. 
         [0007]    Rails of the invention may be of any appropriate shape and size. They typically will be elongated, however. Presently preferred is that they have semi-circular or rectangular (including square) transverse cross-section, although other cross-sectional shapes may be used as well. 
         [0008]    Accordingly, at least some embodiments of the invention will include plates or bodies together with rails and rail supports. A body, from which one or more rail supports outwardly extend, may comprise an electrical connector (such as, but not necessarily, a terminal screw). Preferably a rail support extends from each of its two elongate sides, so that two rails supports are employed in total. Attached to each support, and thereby spaced from the body, is one or more rails. Such attachment advantageously occurs at multiple locations along the length of each rail, although no more than a single attachment location is necessary. Alternatively, any or all of the body, support(s), and rail(s) may be integrally formed. 
         [0009]    It thus is an optional, non-exclusive object of the present invention to provide innovative brush holder assemblies. 
         [0010]    It is another optional, non-exclusive object of the present invention to provide brush holder assemblies omitting conventional boxes for holding brushes. 
         [0011]    It is also an optional, non-exclusive object of the present invention to provide brush holder assemblies utilizing rails for purposes of bounding or retaining brushes in correct positions. 
         [0012]    It is a further optional, non-exclusive object of the present invention to provide brush holder assemblies facilitating cooling of brushes, maintenance of brushes, or both. 
         [0013]    It is, moreover, an optional, non-exclusive object of the present invention to provide brush holder assemblies in which brushes may be supported along all, or substantially all, of their lengths by rails. 
         [0014]    Other objects, features, and advantages of the present invention will be apparent with reference to the remaining text and the drawings of this application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1A  is a perspective view of an exemplary brush holder assembly of the present invention. 
           [0016]      FIG. 1B  is a side view of the assembly of  FIG. 1A . 
           [0017]      FIG. 1C  is a top view of the assembly of  FIG. 1A . 
           [0018]      FIGS. 2A-C  correspond, respectively, to  FIGS. 1A-C  but also illustrate a brush positioned within the assembly. 
           [0019]      FIG. 3  provides a side view similar to that of  FIG. 2B  but for a first alternate brush holder and illustrating a spring and electrical lead. 
           [0020]      FIG. 4  is a top view of a second alternate brush holder assembly consistent with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Depicted in  FIGS. 1A-C  is a version of brush holder assembly  10 . Assembly  10  may comprise plate or body  14 , rails  18 , and rail supports  22 . It also may include an electrical connector, shown as being terminal screw  26 , and optionally a bore  30  for receiving a handle (for example). 
         [0022]    Body  14  may be elongate and configured for connection to another object. It may (but need not necessarily) be generally rectangular in shape and define nominally top surface  34  (in which bore  30  may be formed), first and second sides  38  and  42 , respectively, and face  46  spanning the sides  38  and  42 . One or more elongate supports  22  may connect to one or more of sides  38  and  42 . As shown in  FIGS. 1A-C , support  22 A connects to side  38 , whereas support  22 B connects to side  42 . Such connection may occur in any appropriate manner, or supports  22  may be integrally formed with body  14 . 
         [0023]    Attached to each support  22  may be rail  18 . Each rail  18  too is elongate and preferably of length exceeding—or at least approximating—that of brush B (see  FIGS. 2A-C ). Each rail  18  additionally is of width less than the width of its associated support  22 , so that support  22  spaces the rail  18  from face  46 . FIGS  1 A-B show two fasteners  50  attaching rail  18 A to support  22 A, for example, although other connection means (including integral formation) may be employed instead for either or both of rails  18 A and  18 B. 
         [0024]    Rails  18  may have semi-cylindrical shape, with their flat portions  54  abutting supports  22 . Curved portions  58 , by contrast, are configured to be received by corresponding curved cut-outs  62  in brush B. Cut-outs  62  extend the length of opposing sides  66  and  70  of brush B;  FIGS. 2A-C  illustrate rails  18  received by cut-outs  62  so as to position brush B within assembly  10 . 
         [0025]    As depicted especially in  FIGS. 2A-B , each support  22  may be generally “C” shaped in side view. Because only the shorter, flange portions  74  of the “C” together with rails  18  are adjacent each side  66  or  70  of brush B, substantial portions of sides  66  and  70  remain uncovered. Similarly, although face  78  of brush B abuts face  46  of body  14 , opposed face  82  of brush B is completely uncovered. Because exposed, these portions  66  and  70  and face  82  of brush B may be more easily cooled and maintained than if a box were used. Stated differently, because the perimeter (comprising sides  66  and  70  and faces  78  and  82 ) of brush B is not surrounded (as it would be if a box were employed), it is easier to cool the brush B and maintain the brush holder. 
         [0026]      FIG. 3  shows ribbon spring  86 , which may bias brush B toward a rotating device (as described in the Eger patent). Also illustrated in  FIG. 3  are at least one lead L configured to provide electrical connection between brush B and terminal screw  26 . Support  22 A additionally is depicted as including three fasteners  50  for attachment of the corresponding rail  18 , thus providing a first alternate version of assembly  10  denoted assembly  10 ′. 
         [0027]      FIG. 4 , finally, illustrates in top view a second alternate version of assembly  10 , denoted assembly  10 ″. Assembly  10 ″ may be similar to either of both of assemblies  10  and  10 ′, albeit with rails  18 ″ forming a rectangular prism, or generally so, rather than semi-cylindrical in shape. Cut-outs  62 ″ of brush B consequently likewise are generally rectangular so they may receive rails  18 ″. Persons skilled in the art of the invention will recognize that the rails and cut-outs need not have either semi-cylindrical or rectangular prismatic shapes, but rather may be shaped in any desired complementary manners. 
         [0028]    The foregoing is provided for purposes of illustrating, explaining, and describing exemplary embodiments and certain benefits of the present invention. Modifications and adaptations to the illustrated and described embodiments will be apparent to those skilled in the relevant art and may be made without departing from the scope or spirit of the invention.