Patent Application
20070136969
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.
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.
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.
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.
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.
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.
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.
As shown in
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.
As depicted in
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.
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.
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.
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.
