Patent Abstract:
The present invention is a rotary brushing tool and method of constructing the rotary brushing tool. The rotary brushing tool comprises a hub portion and a wheel portion. The hub portion has a pair of hub elements, where each hub element includes a central opening, an annular retaining plate portion that extends radially from the central opening, and a tubular portion that extends axially from the central opening. Placing the tubular portions of the hub elements in opposition forms a hub channel that extends radially from the central opening. The wheel portion includes bristles arranged in the hub channel to extend substantially radially from the central opening, and a castable material for retaining the bristles. Pouring the castable material into the hub channel and allowing it to cure, forms a hub that retains the bristles.

Full Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates, in general, to rotary brushing tools having non-woven bristles that extend radially from a central hub. In particular, the present invention encompasses a rotary brushing tool having non-woven bristles that extend radially from a central hub which is constructed to produce a one-piece integral structure with a consistent internal diameter.  
       BACKGROUND OF THE INVENTION  
       [0002]     Rotary brushing tools are widely used in industry for cleaning, polishing, deburring, finishing, and burnishing metals and other materials. Rotary brushing tools having a one-piece integral hub structure are desirable because the structural rigidity of such tools will produce a finer surface finish and increase the life of the tool.  
         [0003]     One way of making rotary brushing tools having a one-piece integral hub structure involves placing bundles of non-woven bristles in a fixture, pouring an epoxy or similar material to form the hub into a mold, and allowing the material to cure to form a finished hub. However, the curing characteristics of the material can change from batch to batch and even within the same batch given changes in environmental conditions such as temperature and humidity. These changes to the curing characteristics of the material cause the internal diameter of the hub to fluctuate and possibly be outside desired tolerances. If the internal diameter of the hub is too small, the hub will not fit on an arbor. If the internal diameter of the hub is too large, the brush will just spin idly on the arbor. Either way, when the internal diameter of the hub fails to meet desired tolerances, the brush is essentially useless.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention is a rotary brushing tool and method of constructing the rotary brushing tool. The rotary brushing tool comprises a hub portion and a wheel portion. The hub portion has a pair of hub elements, where each hub element includes a central opening, an annular retaining plate portion that extends radially from the central opening, and a tubular portion that extends axially from the central opening. Placing the tubular portions of the hub elements in opposition forms a hub channel that extends radially from the central opening. The wheel portion includes bristles arranged in the hub channel to extend substantially radially from the central opening, and a castable material for retaining the bristles. Pouring the castable material into the hub channel and allowing it to cure, forms a hub that retains the bristles. An advantage of this approach is that it allows the entire hub area to be filled with bristles to give maximum fill density. This eliminates bare spots and gaps in the face of the brush, for example. In one embodiment, the hub channel substantially envelops the castable material before curing. In another embodiment, the hub channel substantially envelops the castable material after the curing process. The inner diameter of the tubular portion enables a user to secure the rotary brushing tool on an arbor.  
         [0005]     In one embodiment, the tubular portion joins an inner circumference of the annular retaining plate portion. The connection further comprises a stepped portion and a flange. The stepped portion has an annular surface. The flange connects the stepped portion to the inner circumference of the annular retaining plate portion. An inner circumference of the annular surface joins the tubular portion.  
         [0006]     In another embodiment, the annular retaining plate portion for each hub element further comprises a bead located on a side of the annular retaining plate portion inside the hub channel. The bead is operative to apply pressure to the bristles held in the hub channel and may connect to the outer circumference of the annular retaining plate portion. By applying pressure to the bristles, the bead increases the width of the bristles at the outer circumference of the wheel portion of the rotary brushing tool.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The accompanying figures illustrate details of a method of making a rotary brushing tool having non-woven bristles that extend radially from a central hub which is constructed to have a one-piece integral structure with a consistent internal diameter. In the figures, elements that have like reference numbers and designations refer to like elements.  
         [0008]      FIG. 1  is a perspective view depicting an embodiment of a rotary brushing tool constructed with a pair of hub flanges according to the invention.  
         [0009]      FIG. 2A  and  FIG. 2B  are plan views of a hub flange shown in  FIG. 1 .  
         [0010]      FIG. 3A  is a cross-sectional view of one embodiment of a hub flange shown in  FIG. 1 .  
         [0011]      FIG. 3B  is a cross-sectional view of another embodiment of a hub flange shown in  FIG. 1 .  
         [0012]      FIG. 4  is a cross-sectional view of the rotary brushing tool shown in  FIG. 1 , taken through line  4 - 4 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0013]     As shown in  FIG. 1 , a rotary brushing tool  10  according to the invention comprises an annular wheel having a hub and bristles  11  that extend substantially radially from the hub. A pair of hub flanges  20 ,  30  bound the hub. Each hub flange forms one side of the hub. Each hub flange comprises an annular retaining plate portion  21 , a stepped portion  22 , and an axially extending cylindrical tubular portion  23 . While the disclosed embodiments include a stepped portion  22  or  32  (see the discussion of  FIG. 4 ), the stepped portion is not crucial to the invention and may be omitted if desired. In the latter case, the annular retaining plate would join the cylindrical tubular portion  23  or  33  directly and make a smooth, not stepped, transition to cylindrical tubular portion  23  or  33 .  
         [0014]     The hub of rotary brushing tool  10  preferably has a substantially cylindrical shape to facilitate the use of brushing tool  10  as a rotary tool. However, the shape of the hub may be adapted as required by the shape of the arbor, and may for example, be elliptical, square, hexagonal, etc. Thus, even though the invention description is in the context of a cylindrical rotary brushing tool, the invention can be readily adapted for other shapes as well. Preferably, the construction of the hub comprises embedding bristles  11  in a molded, curable epoxy resin or polymer material. In one embodiment, each individual bristle filament has a uniform length and is made of non-woven materials. However, other bristle configurations will be within the scope of the invention.  
         [0015]      FIG. 2A  and  FIG. 2B  are plan views of a hub flange shown in  FIG. 1 .  FIG. 2A  illustrates a plan view of hub flange  20  from the perspective of looking into the hub from the near side of rotary brushing tool  10 . From this perspective, the only visible elements of hub flange  20  are annular retaining plate portion  21  and stepped portion  22 .  FIG. 2B  illustrates a plan view of hub flange  20  from the perspective of looking from the opposite side of rotary brushing tool  10  to the exterior, near side of rotary brushing tool  10 . From this perspective, the only visible elements of hub flange  20  are annular retaining plate portion  21 , stepped portion  22 , and axially extending cylindrical tubular portion  23 .  
         [0016]      FIG. 3A  is a cross-sectional view of one embodiment of a hub flange shown in  FIG. 1 . Hub flange  20  shown in  FIG. 3A  comprises annular retaining plate portion  21 , stepped portion  22 , and axially extending cylindrical tubular portion  23 . Annular retaining plate portion  21  includes an inner circumference and an outer circumference. A flange  24  on the inner circumference of annular retaining plate portion  21  connects annular retaining plate portion  21  to stepped portion  22 . The surface plane of annular retaining plate portion  21  is substantially parallel to the surface plane of stepped portion  22 . Stepped portion  22  includes an inner circumference and an outer circumference. The outer circumference of stepped portion  22  connects to flange  24  on the inner circumference of annular retaining plate portion  21 . The inner circumference of stepped portion  22  connects to axially extending cylindrical tubular portion  23 . The surface plane of axially extending cylindrical tubular portion  23  is substantially perpendicular to the surface plane of stepped portion  22 .  
         [0017]      FIG. 3B  is a cross-sectional view of another embodiment of a hub flange shown in  FIG. 1 . Hub flange  20  shown in  FIG. 3B  comprises annular retaining plate portion  21 , stepped portion  22 , axially extending cylindrical tubular portion  23 , and bead  25 . Annular retaining plate portion  21  includes an inner circumference and an outer circumference. The outer circumference of annular retaining plate portion  21  connects to bead  25 . Bead  25  is a raised surface on the inner wall of annular retaining plate portion  21  that slopes inwardly from the outer circumference of annular retaining plate portion  21  and inwardly from a point between the inner circumference and the outer circumference of annular retaining plate portion  21 . A flange  24  on the inner circumference of annular retaining plate portion  21  connects annular retaining plate portion  21  to stepped portion  22 . The surface plane of annular retaining plate portion  21  is substantially parallel to the surface plane of stepped portion  22 . Stepped portion  22  includes an inner circumference and an outer circumference. The outer circumference of stepped portion  22  connects to flange  24  on the inner circumference of annular retaining plate portion  21 . The inner circumference of stepped portion  22  connects to axially extending cylindrical tubular portion  23 . The surface plane of axially extending cylindrical tubular portion  23  is substantially perpendicular to the surface plane of stepped portion  22 .  
         [0018]     As depicted in  FIG. 3B , bead  25  applies pressure on the bristles  11  held in the annular channel  12  (see the description of  FIG. 4 ). When bead  25  is present, the cured epoxy or polymer material will hold the bristles  11  in a fanned out configuration and make rotary brushing tool  10  slightly wider at the outer circumference of the bristles  11  than at the hub  13 . This is advantageous when a user needs a wider brush. Thus, the user of rotary brushing tool  10  can customize the brush by stacking several brushes axially, from hub-to-hub, to obtain a desired brush width. If the bristles  11  did not flare out at the outer circumference, there would be a gap caused by the hub flanges when stacking the brushes together. Flaring the bristles  11  outwardly effectively eliminates the gaps and provides the user with a wider brush with a continuous brushing surface having no gaps.  
         [0019]     The pressure applied by bead  25  causes the bristles to fan out slightly at the outer circumference of rotary brushing tool  10 . In one embodiment, an inward slope of 30 degrees from the surface plane of annular retaining plate portion  21  creates a raised surface for bead  25  that causes the bristles  11  to fan out sufficiently at the outer circumference of rotary brushing tool  10  to eliminate gaps when stacking multiple brushes. In another embodiment, an inward slope of 90 degrees from the surface plane of annular retaining plate portion  21  creates a flange surface for bead  25  that causes the bristles  11  to fan out sufficiently at the outer circumference of rotary brushing tool  10  to eliminate gaps when stacking multiple brushes. The flexibility, elasticity, and resiliency of bristles  11  determine the inward slope necessary to cause a fan-out of the bristles  11  at the outer circumference of rotary brushing tool  10 .  
         [0020]      FIG. 4  is a cross-sectional view of the rotary brushing tool shown in  FIG. 1 , taken through line  4 - 4 . The cross-sectional view illustrates that an annular channel  12  substantially envelopes hub  13  and that bristles  11  extend substantially radially from hub  13 . Thus, hub flange  20  substantially envelops the right side of hub  13  and hub flange  30  substantially envelops the left side of hub  13 . Hub flange  20 , as described in the discussion of  FIG. 3A , comprises annular retaining plate portion  21 , stepped portion  22 , axially extending cylindrical tubular portion  23 , and flange  24 . Hub flange  30  comprises annular retaining plate portion  31 , stepped portion  32 , axially extending cylindrical tubular portion  33 , and flange  34 . The structure and function of the elements comprising hub flange  30  are similar to the corresponding elements of hub flange  20 .  
         [0021]     The method of constructing the hub flange comprises placing axially extending cylindrical tubular portion  23  in opposition to axially extending cylindrical tubular portion  33 . Placing the axially extending cylindrical tubular portions  23 ,  33  in opposition forms an annular channel  12  that opens radially outward from rotary brushing tool  10 . The method further comprises placing bristles  11  in annular channel  12 , and casting an epoxy resin or other polymer material into the annular channel  12 . In one embodiment, annular channel  12  substantially envelops the castable material before curing. In another embodiment, annular channel  12  substantially envelops the castable material after curing. Regardless, once cured, the epoxy resin or other polymer material holds the bristles  11  in place in the annular channel  12 . The inner circumference of the annular channel  12  defines a central opening that allows a user to place rotary brushing tool  10  onto an arbor.  
         [0022]     Adding hub flanges  20 ,  30  on the right and left side of rotary brushing tool  10  before casting the epoxy resin or other polymer material into the annular channel  12  holds the bristles  11  in place and determines the dimensions of hub  13  independent of the casting process. Since hub flanges  20 ,  30  are pre-made and not dependent on the cast epoxy or other polymer material, the diameter of the central opening formed by mounting the axially extending cylindrical tubular portions  23 ,  33  in opposition is always consistent. Furthermore, since the construction of pre-made hub flanges  20 ,  30  achieves much higher tolerances than a cast hub, a brush manufacturer can be assured that the internal diameter of every brush that uses the pre-made hub will be consistent, regardless of the epoxy resin or other polymer material used to encapsulate the bristles or of the curing conditions of the material.  
         [0023]     Although the disclosed embodiments describe a fully functioning rotary brushing tool and method of construction to produce a rotary brushing tool having non-woven bristles that extend radially from a central hub, which is constructed to produce a one-piece integral structure with a consistent internal diameter, the reader, should understand that other equivalent embodiments exist. Since numerous modifications and variations will occur to those reviewing this disclosure, the rotary brushing tool and method of construction is not limited to the exact construction and operation illustrated and disclosed. Accordingly, this disclosure intends all suitable modifications and equivalents to fall within the scope of the claims.

Technology Classification (CPC): 0