Technical Field

[0001] This invention relates to an abrasive brush comprising a plurality of bristles of brush that are in a bound form. Background of the Invention

[0002]

In the field of grinding the surface or end-surface of a metal, such as a steel plate, etc., an abrasive brush comprising, as bristles of brush, monofilaments consisting of synthetic resins that comprise abrasive particles has been used.

The abrasive brush of this type that has widely been used is one that consists of bristles of brush that comprise a polyamide resin, like nylon, that contains abrasive particles that consist of silicon carbide, aluminum oxide, etc. For example, Patent Document 1 discloses bristles of brush for an abrasive brush, which pieces include a polyamide resin to which is added the abrasive particles comprising silicon carbide.

Patent document 1 : Publication of Laid-Open Japanese Patent Application, Publication No. 2002-283242

Summary of the Invention

The Problem to be Solved by the Invention

[0003] Recently hard materials such as silicon blocks or ceramic materials are increasing as objects to be ground. Particularly the demand for removing minor cracks on the surface of the hard materials is increasing. But conventional abrasive brushes are insufficient to produce an effective grinding power and thus cannot fully meet the requirements for grinding., [0004] In view of the situation, the present invention aims to provide an abrasive brush that has a sufficient grinding power and that is suitable for grinding hard materials.

Means to Solve the Problems [0005]

The present invention is to provide an abrasive brush that can resolve these problems. The abrasive brush of claim 1 provides a technical means wherein it comprises a plurality of bristles of brush, a binding material that binds the plurality of bristles of brush, by coating the outer circumference of the surfaces of the plurality of bristles of brush, and a brush holder that holds the end parts of the plurality of bristles of brush that are bound, and that fastens it to a driving part of an abrasive brush apparatus. That part drives the abrasive brush, the end part of the plurality of bristles of brush that are bound being easily fastened to or removed from the driving part of the abrasive brush apparatus. The bristles of brash are monofilaments consisting of a polyester resin that comprises the abrasive particles that are made of the diamond particles having their surfaces coated with nickel or a metal alloy consisting mainly of nickel. [0006]

In the invention of claim 1, the polyester resin that constitutes the bristles of brush is harder and more elastic than the resin material that has been conventionally used as monofilaments. Thus greater grinding power can be obtained. Further, the abrasive brash can grind the object while the diamond particles, which have by far greater hardness, can be exposed above the surfaces of the monofilaments. Thus greater grinding power can be obtained. Also, by coating the surfaces of the diamond particles with nickel or a metal alloy consisting mainly of nickel, the concavities and convexities that are larger than those on the surfaces of the diamond particles are formed on the surfaces of the abrasive particles. The concavities and convexities produce the anchoring effects whereby the diamond particles are more rigidly anchored to the resin material and tend to not come off the bristles of brush. As a result, higher grinding power can be maintained for a longer time. The abrasive brush of the present invention is particularly useful for removing minor cracks on the surface of hard material, because with the brush-grinding, no excessive force affects the object to be ground compared with a force that is applied by grinding by a grindstone. [0007]

The abrasive brush of claim 2 provides a technical means wherein the polyester resin of the bristles of brush of claim 1 comprises 60 molar % or more of ethylene-2,6-naphthalate units and has a diameter 0.4-1.0 mm.

[0008]

As stated in claim 2, a polymer that comprises 60 molar % or more of ethylene-2,6-naphthalate units, for example, a polyethylene naphthalate resin, can be used usefully as a polyester resin. The monofilaments consisting of the polyethylene resin that comprises 60 molar % or more of ethylene-2,6-naphthalate units has high stiffness. So, it can advantageously increase the grinding power. Also, each of the diameters of the bristles of brush should preferably be within 0.4-1.0 mm. If the diameter is below 0.4 mm, the stiffness of the bristles of brush decreases. Then, sufficient grinding power cannot be obtained. If the diameter is above 1 mm, the hardness of the bristles of brush become higher than conventional materials and the stiffness of the bristles of brash becomes too high. And then the bristles of brash will become brittle and will be easily broken.

[0009]

The abrasive brash of claim 3 provides a technical means wherein the bristles of brash of claim 1 or 2 comprise 45 — 65 wt% of nickel or the metal alloy consisting mainly of nickel that coats the surfaces of the diamond particles, based on the weight of the abrasive particles.

[0010]

As stated in claim 3, the amount of nickel or the metal alloy consisting mainly of nickel that coats the surfaces of the diamond particles should preferably be 45 — 65 wt% of the total weight of the abrasive particles. If the amount is below 45 wt%, sufficiently large concavities and convexities cannot be formed on the surfaces of the abrasive particles, thus producing a binding force that only poorly binds the particles to the bristles of brush. As a result, a greater number of abrasive particles will come off during grinding and the efficiency of the grinding will decrease. If the amount is above 65 wt%, the ratio of the surfaces of the abrasive particles that are exposed will decrease. As a result, the efficiency of the grinding will also decrease.

[0011]

The abrasive brush of claim 4 provides a technical means wherein the bristles of brush of claim 1 or 2 comprise 10 — 40 pts.wt of the abrasive particles, based on 100 pts.wt of the polyester resins.

[0012]

As stated in claim 4, the amount of the abrasive particles that are included in the bristles of brush should preferably be 10 — 40 pts.wt, based on 100 pts.wt of the polyester resins. If the amount is below 10 pts.wt, a sufficient amount of abrasive particles is not exposed above the surfaces of the monofilaments and as a result, sufficient grinding power is not obtained. If the amount is above 40 pts.wt, the strength of the monofilaments decreases and they become easily broken.

[0013]

The abrasive brush of claim 5 provides a technical means wherein the bristles of brush of claims 1 or 2 comprise abrasive particles having an average diameter of

5μm — 150μm.

[0014]

As stated in claim 5, the average diameter of the abrasive particles should preferably be 5μm — 150μm. If the average diameter is below 5μm, sufficient grinding power is not obtained. If the average diameter is above 150μm, the strength of the monofilaments decreases and they .become easily broken. [0015]

The abrasive brush of claim 6 provides a technical means wherein the abrasive brush of claim 1 or 2 comprises a brush holder, the brush holder comprising insert holes, into each of which the end parts of the plurality of bristles of brush that are bound are inserted, and a holding part that is easily fastened to or removed from a driving part of the abrasive brush apparatus, which part drives the abrasive brush.

[0016] The abrasive brush of claim 6 can be easily produced only by inserting the end parts of the plurality of bristles of brush that are bound into the insert hole of the brush holder and by fastening them to the hole. Also, the abrasive brush apparatus has a holding part that is easily fastened to or removed from the driving part of the abrasive brush apparatus. The driving part drives the abrasive brush. So, the efficiency of the grinding can be improved.

The Brief Description of the Drawings

[0017]

Fig. 1 illustrates a part of the cross section of the abrasive brush in one embodiment of the present invention.

Fig. 2 shows how the abrasive brush is attached to the brush-fastening tool of the abrasive brush apparatus.

Fig. 2(A) shows a frontal view of the abrasive brush apparatus. One part of the view is omitted. Fig. 2(B) shows the base view of Fig. 2(A). Fig. 3 illustrates a cross sectional view of a silicon block before and after it is ground by the abrasive brush in one embodiment of the present invention. Fig. 3(A) illustrates a cross sectional view of a silicon block before it is ground by the abrasive brush. Fig.

3(B) illustrates a cross sectional view of a silicon block after it is ground by the abrasive brush. Embodiment of the Invention

[0018]

The abrasive brush of the present invention is explained in referring to the drawings.

[0019]

As shown in Fig. 1, the abrasive brash 10 comprises a plurality of bristles of brush 11 that contain the diamond particles as abrasive particles.

The bristles of brush 11 are bound by the binding material 12 around their outer circumference 11a, wherein the end parts 11 b of the plurality of bristles of brush 11 that are bound are held by the brush holder 13.

In the present embodiment, the brush holder 13 comprises the insert hole 13 a, into each of which the end parts lib of the plurality of bristles of brush 11 are inserted and the holding parts 13 b, which are easily fastened to or removed from the driving part (a fastening member 21 in Fig. 2 corresponds to this) of an abrasive brush apparatus, which driving part drives the abrasive brash. The end parts lib of the plurality of bristles of brash 11 are fastened to the insert hole 13 a, by, for example, an adhesive.

[0020] The bristles of brash 11 are monofilaments made of a polyester resin that has a circular cross section, and that contain the abrasive particles that are the diamond particles, the surfaces of which are coated with nickel or a metal alloy consisting mainly of nickel. These monofilaments are manufactured by melt-spinning the polyester resin after mixing it with the predetermined amount of abrasive particles, and if necessary, by extending the polyester resin thus melt-spun.

[0021]

The polyester resin of the abrasive brash 10 that uses the bristles of brash 11 thus obtained is harder and more elastic than the nylon resin that has been conventionally used as monofilaments. Thus it has greater grinding power. Also, the diamond particles, which have extremely high hardness, and that are exposed above the surfaces of the monofilaments, can have an increased grinding power.

[0022] The polyester resins used in the present invention comprise polyethylene naphthalate, polyethylene telephthalate, polymethylene telephthalate, polytetramethylene telephthalate, polypropylene telephthalate, polymethylene naphthalate, polytetramethylene naphthalate, polypropylene naphthalate, or a copolymerized polyester that includes any of these as main components.

[0023]

The polyester resins used in one embodiment of the present invention is a polymer that comprises 60 molar % or more of ethylene-2, 6-naphthalate units. Thus a suitable polyethylene naphthalate resin can be used. The monofilaments made of a polyester resin that comprises 60 molar % or more of ethylene-2, 6-naphthalate units are preferably used, because they have higher stiffness and thus the grinding power can be increased. If the polyethylene naphthalate resin is less than 40 molar %, the polyester resin can include a dicarboxylic acid component, such as telephthalic acid, isophthalic acid, and phthalic acid, and a diol component, such as ethylene glycol, propylene glycol, and tetramethylene glycol.

[0024]

The abrasive particles of the bristles of brush 11 are formed such that the surfaces of the diamond particles are coated with nickel or a metal alloy consisting mainly of nickel. The abrasive particles used in the present embodiment are diamond particles, the surfaces of which are coated with nickel by nonelectrolytic plating.

[0025]

Generally the diamond particles do not have any determinate form and the concavities and convexities (roughness) of the surfaces are limited. Thus if the particles are mixed with resin materials in that form, the binding force between the particles and the resin materials is small and the particles tend to easily come off the bristles of brush during grinding. While being coated by nickel or a metal alloy consisting mainly of nickel, the concavities and convexities that are larger than those on the surfaces of the diamond particles are formed, whereby the effects to anchor the particles to the resins materials are produced, causing the particles to not easily come off the bristles of brush. In this way the abrasive brush of the present invention can continue grinding for a longer time, while maintaining the high grinding power.

[0026]

Various methods to coat the surfaces of the particles can be used other than the nonelectrolytic plating, such as carrying out nonelectrolytic plating after spattering, and attaching physically a nickel or metal alloy to the diamond particles by means of mechanical ironing.

[0027]

The amount of the nickel or the metal alloy consisting mainly of nickel that is used for coating is preferably 45 — 65 wt% of the total amount of the abrasive particles. If the amount is below 45 wt%, the concavities and convexities are not sufficiently formed on the surfaces of the abrasive particles and the binding force between the abrasive particles and the bristles of brush is small. As a result, a larger number of the abrasive particles will come off during grinding and the efficiency of the grinding will be lower. If the amount is above 65 wt%, the ratio of the surfaces of the abrasive particles that are exposed will decrease. As a result, the efficiency of the grinding will decrease.

[0028]

If the diameters of the diamond particles are larger, the grinding power increases, resulting in the increased efficiency of the grinding. If the diameters of the diamond particles are smaller, large grinding power _. cannot be obtained. But the roughness of the surface of the object that was ground is able to be made smoother. The average diameter of the diamond particles is preferably 5 — 150 μm. If the average diameter is below 5 μm, sufficient grinding power cannot be obtained. If the average diameter is above 150 μm, the strength of the monofilaments of the bristles of brush decreases, and they become easily broken.

[0029]

The amount of the abrasive particles included in the bristles of brush 11 is preferably 10 — 40 pts.wt., based on 100 pts.wt, of the bristles of brush 11 (polyester resin). If the amount is below 10 pts.wt., a sufficient amount of the abrasive particles are not exposed above the surfaces of the bristles of brush 11 and a sufficient grinding power cannot be obtained. If the amount is above 40 pts.wt., the strength of the monofilaments of the bristles of brush decreases, and they become easily broken.

[0030] The diameter of the bristles of brush 11 (monofilaments) is preferably in the range of 0.4 — 1.0 mm. If the diameter is below 0.4 mm, the stiffness of the bristles of brash 11 becomes low and as a result, sufficient grinding power cannot be obtained. If the diameter is above 1.0 mm, the stiffness of the bristles of brush will be too high and the bristles of brash will become brittle and will be easily broken.

[0031]

The binding material 12, consisting of resin materials, such as rubber, silicon rubber, and polyvinyl chloride resins, binds the bristles of brush 11 by coating them around their outer circumference 1 Ia. In the present embodiment, the tip portions of the bristles of brash 11 are seen slightly exposed in Fig. 1. This shows the trace where a provisional fastening member (not shown) that bound the tip parts of the bristles of brash 11 was placed during the process of coating the bristles of brash 11 with the resin materials around their outer circumference 11a. The provisional fastening member is removed after the binding material _. 12 that coats (is painted on) the outer circumference 11a of the bristles of brash 11 is dried and becomes solid. A string, a rubber ring, etc., can be used as provisional fastening member material.

[0032] -

The binding material 12 thus constituted can produce sufficient stiffness at the tips of the bristles of brush 11 even if the bristles of brush 11 become longer. This is because the binding material 12 can bind the bristles of brush 11, and restrain them from being deformed in the direction of the grinding. In this way the abrasive brush 10 can produce high grinding power. Further, the tips of the bristles of brush 11 can always be exposed during grinding, depending on the wear of the tips of the bristles of brush 11. This is because as the binding material 12 is made of resin materials, and when the tip portions of the bristles of brush 11 wear in the grinding process, the binding material 12 gradually breaks or wears in accord with the wear of the tips of the bristles of brush 11. This enables the tips of the bristles of brush 11 to have the desired stiffness and allows the grinding to be carried out with the tips of the bristles of brush 11 always being exposed.

[0033]

The binding material 12 can be formed not only by painting the bristles of brush 11 with the resin material but also by heating a tape or tube and adhering it to the bristles of brush 11. Further, if sufficient stiffness can be obtained, not all the length along the bristles of brush need be coated around their outer circumference 11a. The length of the binding material 12 or the location of the outer circumference 11a of the bristles of brush that should be bound can be freely decided.

[0034]

The abrasive brush 10 of the present embodiment, wherein the abrasive brush 10 is fitted to a brush-fastening tool 20 of the abrasive brush apparatus (not shown), is below explained, in referring to Figs. 2(A) and 2(B).

[0035] As shown in Figs. 2(A) and 2(B), the brush-fastening tool 20 comprises a turning member 22 of a cylindrical shape having an upper lid, to which turning member 22 the turning shaft 30 of the abrasive brush apparatus is connected, and comprises, inside the turning member 22, a brush-fastening member 21, wherein a plurality of the abrasive brushes 10 can be attached by tightening a fastening screw 25 and wherein a position in the vertical direction of the plurality of the abrasive brushes 10 can be fixed by tightening a fixing screw 26, the position in the vertical direction of the plurality of the abrasive brushes 10 being movably adjusted by loosening the fixing screw 26; also comprises a sliding axis 24 disposed vertically at the center of the turning member 22 and on the extension of the turning shaft 30, allowing the brush-fastening member 21 to move by sliding when the position of the abrasive brush in the vertical direction is adjusted; and further comprises a supporting member 23 that adjusts the positions of the tip portions of the bristles of brush 11 of the abrasive brushes 10 that are attached to the lower opening end portion of the turning member 22, a supporting member 23 being easily fastened to or removed from the lower open-end portion of the turning member 22.

[0036]

In the present embodiment, fifteen fixing holes 21a, which the abrasive brushes 10 are easily fastened to or removed from, are concentrically formed with predetermined space between each of them. A magnet 21b is attached to the surface of each fixing hole 21a.

When the brush holder 13 is inserted into the fixing hole 2Ia ₅ the magnet 21b attracts and holds the brush holder 13. The abrasive brush 10 is fixed to the fastening member

21 by fastening the brush holder 13 with the fastening screw 25. As seen above, as the abrasive brush 10 can be easily fastened or removed. So, the efficiency of such work can be improved.

[0037]

Further, a bush 21c is provided at the center of the brush-fastening member 21, so that the abrasive brush 10 can be moved up and down, sliding along the sliding axis 24 that pierces through the brush-fastening tool 20.

[0038]

A through-hole 23a, having a bush 23b, into which the bristles of brush are inserted, is formed in the supporting member 23. After a certain length of the tips of the bristles of brush are pushed out of the outer surface of the supporting member 23 and toward the . side of the object to be ground, the position of the pushed-out tips of the bristles of brush 11 is determined by tightening the fixing screw 26.

[0039]

Next, the turning member 22 and brush-fastening member 21 of the brush-fastening tool

20 turn as one body when the turning shaft 30 of the abrasive brush apparatus rotates. In this way a plurality of the abrasive brushes 10 attached to the brush-fastening member

21 can turn around the turning shaft 30 as its center of rotation. A displacement mechanism (not shown) of the abrasive brush apparatus presses the abrasive brushes 10 of the brush-fastening tool 20 against the object to be ground. The object is thus moved relative to the abrasive brushes and it can be ground.

[0040] When the tips of the bristles of brush 11 are worn away and then when the portions of the bristles of brush 11 that protrude from the through-hole 23 a of the supporting member 23 become shorter, the brush-fastening member 21 is moved toward the supporting member 23, making a certain predetermined portion of the bristles of brush 11 protrude from the through-hole 23a toward the side of the object to be ground. Thus the grinding can continue. In this way, the bristles of brush 11 can be used to their maximum capacity without any unused portion being left, resulting in the reduced number of changes of the abrasive brushes 10, which changes would otherwise be required in a greater number because of the wear of the bristles of brush 11.

[0041] The abrasive brash 10 of the present invention is suitably applied to the grinding of hard materials, such as silicon blocks, and ceramic materials. If there are minor cracks on the surfaces of the hard materials, they will lead to the destruction or damage of the hard materials in subsequent processes or during their use, because the cracks will cause a significant decrease in strength. So, it is important to remove these minor cracks. The abrasive brush 10 of the present invention has a large grinding power such that it can not only grind these hard materials efficiently, but it does not produce new cracks during its grinding. This is because unlike the grinding carried out by a grindstone, no excessive force affects the object to be ground. Thus the abrasive brush 10 is suitably used, particularly for removing minor cracks on the surfaces of the hard materials.

[0042]

(An alternative example)

The cross section of the bristles of brash 11 can be an oval, triangle, rectangle, or any other shape, besides a circle. The brush holder 13 can be made from various structural materials. For example, the end part 1 Ib can be coated with a resin material. Also, Fig. 1 shows the brash holder 13 where it has a shape of a circle pillar, but the shape is not limited to this shape. The shape can be suitably selected, depending on the shape of the fixing hole 21a of the brash-fastening member 21.

[0043]

(An example)

An example of the grinding using the abrasive brush of the present invention is now explained. As an object to be ground, a single-crystal silicon block formed as a square pillar is used. However, the present invention is not limited to the example given below.

[0044]

In the present example, the monofilaments listed as abrasive brashes A — D in Table 1 are used as bristles of brash, which have an OD of 22.6 mm. The length of the brash pieces is 125 mm. For the resin material of the bristles of brash, the polyethylene telephthalate (PEN) is used. The abrasive particles, which are the diamond particles, the surfaces of which are coated with nickel, are used. The amount of the nickel included is 56 weight %. The amount of the abrasive particles included was 20 pts.wt against 100 pts.wt of the amount of the polyethylene telephthalate of the bristles of brush. The diameters of the diamond particles are at level 4, and their diameters decrease in the order of the abrasive brushes A to D.

[045] [Table 1]

[0046]

The grinding (hereafter, the processing of F-surface) of the side face of a single crystal silicon block along the length (hereafter, F-surface) and the processing (hereafter, the processing of R-portion) of the corner portion where F-surface intersects and forms a corner (hereafter, R-portion) were carried out. For the grinding of F-surface, as shown in Fig. 2(B), by using the supporting member 21, the brush holder was arranged to have 15 abrasive brushes and its rotational diameter was arranged to be 180 mm. For the processing of R-portion, the brush holder was arranged to have 5 abrasive brushes and its rotational diameter was arranged to be 60 mm.

[0047]

The grinding conditions were the following: the speed of the rotation of the abrasive brush was 1,720 rpm, the depth of the grinding was 1.0 mm, the processing time was 60 seconds for one processing, and the feed rate of the object to be ground was 10 mm/sec. For processing F-surface, the abrasive brushes were pressed vertically against F-surface, and for the processing of R-portion, the abrasive brushes were pressed against R-portion at an angle of 45 degrees.

[0048]

The depth of grinding and the surface roughness (Ry) after F-surface and R-portion were ground are shown in Table 2. The grinding power decreased from abrasive brushes A to D, in that order. So, in both F-surface and R-portion, the depth of grinding of the abrasive brushes increased from D to A in that order. Particularly, if F-surface was ground with abrasive brush A, the depth of grinding exceeded 100 μm in one processing. So, the grinding could be performed with higher grinding power. The surface roughness decreased from abrasive brushes A to D, in that order. When F-surface was ground with abrasive brushes C and D, a smooth ground surface, which had a surface roughness of 1 μm or less, was able to be obtained.

[0049] [Table 2]

[0050]

In a silicon block, generally the depth of an initial small crack on the surface is about lOOμm. So, to remove the small crack by grinding, the depth of grinding must be more than 1 OOμm. To remove a small crack by grinding and at the same time- to minimize the surface roughness, with an increased efficiency of grinding, for example, abrasive brush D should be used after the grinding is carried out by abrasive brush A. Also, the grinding can be made three times by abrasive brush C. The grinding can be made by using the abrasive brushes, for example, in such a way that several abrasive brush apparatuses (not shown) are lined up in series, and in such a way that several brush-fastening tools 20 of Figs. 2(A) and 2(B), and also the abrasive brushes, are prepared in the order of the decreasing diameters of the abrasive particles (the diameters of the diamond particles). Thus a suitable combination of the abrasive brushes and grinding methods can be selected, based on the conditions for the surface of the object to be ground.

[0051]

Fig. 3 shows a cross section of the silicon block before and after it was ground. Fig.

3(A) shows a cross section of the silicon block before it was ground.

Fig. 3(B) shows a cross section of the silicon block after it was ground. For the grinding, the abrasive brushes were used in the order of A to B, to D. The conditions of grinding were the following: the rotational speed was 1,420 rpm, the depth of grinding by each abrasive brush was 0.5 mm, the processing time of each abrasive brush was 60 sec, and the feed rate of the object to be ground was 10 mm/sec. Before grinding, the silicon block had a crack lOOμm deep on the surface, but it was removed after it was ground.

[0052]

As disclosed above, the abrasive brush of the present invention efficiently grinds a silicon block, which is a hard material, and can produce the desired surface roughness and can be suitably used to remove a small crack on the surface.

[0053]

Effect of the Embodiment of the Invention

The abrasive-brush 10 of the present invention can have an increased grinding power because the polyester resin constituting the bristles of brush 11 is harder than the conventional resin materials used as monofilaments and is more elastic. Also, the grinding power can be greater, because the abrasive brush of the present invention can grind the object with the diamond particles, which have significantly high hardness, and which protrude from the surfaces of the bristles of brush 11. Also, the abrasive brush of the present invention can have the surfaces of the diamond particles coated with nickel or a metal alloy consisting mainly of nickel. So, greater concavities and convexities are formed on the surfaces of the diamond particles, whereby the effects to anchor the particles to the resins materials are produced, preventing the particles from easily coming off the bristles of brush. In this way the abrasive brush of the present invention can maintain high grinding power for a longer time.

In the grinding by the abrasive brushes, no excessive force affects the object to be ground, compared with grinding by a grindstone. So, the abrasive brush of the present invention can be suitably used for removing minor cracks on the surfaces of the hard materials. Further, superior effects can be obtained if the conditions for the grinding are suitably chosen, such as by selecting a suitable polyester resin, and adjusting the amount of nickel or a metal alloy consisting mainly of nickel that is used to coat the surface of a polyester resin or the diamond particles, the amount of abrasive particles contained in the bristles of brush, and the average diameter of the diamond particles.

[0054]

The basic Japanese Patent Application, No. 2009-126189, filed on May 26, 2009, is hereby incorporated in its entirety by reference in the present application.

The present invention will become more fully understood from the detailed description of this specification. However, the detailed description and the specific embodiment illustrate desired embodiments of the present invention and are described only for the purpose of explanation. Various possible changes and modifications will be apparent to those of ordinary skills in the art on the basis of the detailed description. The applicant has no intention to dedicate to the public any disclosed embodiments. Among the disclosed changes and modifications, those that may not literally fall within the scope of the present claims constitute, therefore, a part of the present invention in the sense of the doctrine of equivalents.

The use of the articles "a," "an," and "the," and similar referents in the specification and claims, are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by the context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed.

Symbols

[0055] 10 abrasive brush

11 bristles of brush

12 binding material

13 brush holder 13a insert hole 13b holding part

20 brush-fastening tool