Abstract:
A rotary brush for use with a surface finishing tool with a drive shaft for transmitting rotary motion to the brush. The brush is in the form of a circular disc that supports circumferentially disposed brushing elements, and includes a nut having internal threads for engagement with the drive shaft. The nut extends axially outward from each face of the disc an approximately equal distance to facilitate bi-directional mounting of the brush on the drive shaft.

Description:
BACKGROUND 
       [0001]    This disclosure relates to a method of manufacturing wire brush tools for metal working and other finishing operations. 
         [0002]    It is an object to provide a brushing tool which enables the brushing tool to be mounted bi-directionally, greatly extending the service life of the brush. 
       SUMMARY 
       [0003]    A rotary brush for use with a surface finishing tool is disclosed. The tool has a drive shaft for transmitting rotary motion to the brush. The brush is in the form of a circular disc that supports circumferentially disposed brushing elements, and comprises a nut including internal threads for engagement with the drive shaft. The nut extends axially outward from each face of the disc an approximately equal amount to facilitate bi-directional mounting of the brush on the tool. 
         [0004]    In a further embodiment, also disclosed is a rotary brush, comprising a circular disc defining a plane, a plurality of brushing elements extending radially from the disc around the circumference of the disc and lying substantially in the plane defined by the disc, and a mounting nut located coaxial with the axis of the disc and extending symmetrically on both sides of the disc relative to the plane of the disc for mounting the disc to a drive shaft The brushing elements may comprise wire knots, abrasive bristles, or other suitable brushing elements. 
         [0005]    Also disclosed is a mounting nut for a rotary brush, comprising a body portion having a central bore therethrough, the bore being threaded to engage a correspondingly threaded drive shaft, and a disc-engaging portion located in substantially the center of the body portion for attaching the circular disc to the nut to transmit rotary motion of the drive shaft to the disc through the nut. When the nut is attached to the disc he body portion extends outward from each face of the disc an approximately equal distance. The body portion of the mounting nut may include hex flats on the exterior of the body portion. Also disclosed is a bidirectional mounting system for a rotary disc brush in the form of a circular disc supporting circumferentially disposed brushing elements, comprising an externally threaded drive shaft for producing rotary motion, a nut mountable to the center of the circular disc, the nut having a body portion with first and second ends and a central bore threaded to engage the threaded drive shaft for rotary movement therewith, the nut having a disc-engaging portion in substantially the center of the body portion between the first and second ends for attachment to the disc, the body portion extending outward from the disc-engaging portion an approximately equal distance. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0006]    For the purpose of illustration, the drawings show a form of rotary brush that is presently preferred. However, it should be understood that the brush is not limited to the precise arrangements and instrumentalities shown in the drawings. 
           [0007]      FIG. 1  is a front view of a rotary brush according to the prior art. 
           [0008]      FIG. 2  is a side view of the rotary brush of  FIG. 1 . 
           [0009]      FIG. 3  is a sectional view of the rotary brush of  FIG. 1 , taken along the line  3 - 3  in  FIG. 1 . 
           [0010]      FIG. 4  and  FIG. 5  are simplified illustrations of the manner in which the rotary brush according, to the prior art may be mounted to a surface finishing tool. 
           [0011]      FIG. 6  is a sectional view similar to  FIG. 3  of a rotary brush as disclosed and claimed herein. 
           [0012]      FIG. 7  and  FIG. 8  are simplified illustrations of the manner in which the rotary brush as disclosed and claimed herein may be mounted to the surface finishing tool. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Referring to the drawings, wherein like numerals indicate like elements, there is shown in  FIGS. 1 ,  2 , and  3  a rotary brush  10  according to the prior art. The prior art brush  10  has a disc  12  that supports a plurality radially extending wire knots  14 . Wire knots are formed by passing wire bundles through circumferential perforations located along the edge of disc  12 . Wire knots  14  are formed by looping and twisting the wire bundles around the edge of the disc  12 . 
         [0014]    Disc  12  is sandwiched between side plates  16 . Side plates  16  are formed near the rim to define a bulbous cavity  16  to surround and hold wire knots  14  in place. The extreme ends  18  of side plates  16  are tightly crimped against wire knots  14  in order to restrict pivotal movement of wire knots  14  in the plane of disc  12 . Side plates  16  may be welded to disc  12 . A mounting nut  20  is provided for mounting rotary brush  10  to a drive shaft of a surface finishing tool or other means of imparting rotary motion to the brush. Mounting nut  20  typically has internal threads  22  to enable rotary brush  10  to threadingly engage a correspondingly threaded drive shaft. 
         [0015]    As best seen in  FIGS. 2 and 3 , mounting nut  20  has one side  24  that is swaged or rolled over to help anchor mounting nut  20  to disc  12 . By forming side  24  in that manner, mounting nut  20  can be firmly attached to disc  12  without the need for additional elements such as adhesives, rivets, and the like. Although prior art mounting nut  20  facilitates attachment to disc  12 , it can be seen that mounting nut  20  extends for a distance y on the side of the disc  12  opposite the swaged side  24 . As a result, the rotary brush is asymmetric when viewed from the side as in  FIG. 3 . 
         [0016]    Rotary brush  10  is intended to be mounted to a finishing tool so that the mounting nut  20  faces outward relative to finishing tool  26 , as best seen in  FIG. 4 . That is brush  10  is intended to be mounted on the drive shaft  28  in such a manner that brush  10  rotates within safety guard  30  so that a user&#39;s hands and fingers are shielded from the brush  10  when it is being rotated by finishing tool  26 . Thus, the prior art brush  10  uses the asymmetric mounting nut  20  to encourage the brush  10  to be mounted only one way on the drive shaft  28 , for safety reasons. 
         [0017]    However, mounting brush  10  as shown in  FIG. 4  means that the brush  10  rotates always in the same direction. As the brush  10  is used, the wire knots  14  tend to wear down and become dull, so that the brush  10  becomes less “aggressive” in removing material from a surface to be finished by the brush  10 . To extend the life of a brush  10 , users in the field often remove the brush  10  after it has become worn, turn it over, and remount it to the drive shaft  20  with mounting nut  20  facing inward, as best seen in  FIG. 5 . This effectively causes the brush  10  to rotate in the opposite direction, and presents an unworn, more aggressive face of the wire knows  14  to the surface to be finished. 
         [0018]    Mounting the brush  10  in that manner, however, leads to safety problems. Because of the safety guard, it is sometimes difficult to insert a wrench or other tool to tighten mounting nut  20  to securely attached brush  10  to drive shaft  28 . Failure to adequately tighten mounting nut  20  and securely attach brush  10  to drive shaft  20  can result in the brush becoming loose and flying off the tool at high speed, posing a clear risk of injury to the user, to bystanders, and to property. In addition, because the mounting nut  20  is asymmetric relative to disc  12 , by mounting brush  10  so that mounting nut  20  faces inward, the plane of disc  12 , and consequently wire knots  14 , extend past the safety guard  30 . A rapidly rotating brush  10  extending beyond safety guard  30  poses a clear risk of hand and finger injury, or worse, to the user. 
         [0019]    The brush disclosed and claimed herein overcomes the problems with the prior art brush and enables a rotary brush to be mounted with either surface of the brush disc facing inward relative to the finishing tool. Referring first. to  FIG. 6 , rotary brush  40  has substantially the same structure as brush  10 . Thus, rotary brush  40  includes a disc  42  that supports a plurality of radially extending wire knots  44 . Disc  42  is sandwiched between side plates  46 , and the extreme ends  48  of side plates  46  are tightly crimped against wire knots  44 , all as with brush  10 . 
         [0020]    Rotary brush  40  also includes a mounting nut  50  for mounting rotary brush  40  to a drive shaft  28  of a surface finishing tool  26  or other means of imparting rotary motion to the brush. Mounting nut  50  has internal threads  22  to enable rotary brush  40  to threadingly engage drive shaft  28 . 
         [0021]    Mounting nut  50  extends axially outward from the plane of disc  42  for a distance x on each side of disc  42 . The distance x on one side of disc  42  is approximately equal to the distance x on the opposite side of disc  42 , but exact equality is not necessary. The actual distances may vary slightly, as long as they are approximately the same on both sides of disc  42 . Preferably, distance x is less than the distance y by which mounting nut  20  extends from on one side of prior art brush disc  12  (sec  FIG. 3 ). 
         [0022]    By making extent x of mounting nut  50  less than the extent y of mounting nut  20 , there is greater assurance that, if brush  40  is turned over and mounted on drive shaft  28  the opposite way, safety guard  30  will be able to fully shield wire knots  44  of brush  40 . As best seen in  FIGS. 7 and 8 , when mounted with either surface of disc  42  facing outward, the plane of disc  42  is at approximately the same distance from the finishing tool  26 . That way, brush  40  is fully shielded by safety guard  30  and there are no wire knots  44  that extend an unsafe distance beyond the edge of safety guard  30 . In addition, mounting nut  50  has hexagonal flats on both sides of disc  42 , so that a user can easily reach the hexagonal flats with a wrench or other tool to securely tighten mounting nut  50  to drive shaft  48 . 
         [0023]    It is presently preferred that mounting nut  50  be a single piece. However, mounting nut may comprises two separate halves, one half being attached to one face of the disc  42  and the other half being attached to the other face of the disc  42 . 
         [0024]    The disclosed brush may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of protection claimed.