BRUSH ASSEMBLY

Abstract

A brush assembly has a brush holder rotatable about a rotation axis, a ring brush carried on the holder and having an annular array of radially outwardly projecting bristles, and a stop element fixed adjacent the ring brush, of noncircular section. This stop element extends along and is rotatable about a longitudinal axis generally parallel to the rotation axis and projects into the array of bristles.

Claims

1. A brush assembly comprising: a brush holder rotatable about a rotation axis; a ring brush carried on the holder and having an annular array of radially outwardly projecting bristles; and a stop element fixed adjacent the ring brush, of noncircular section, extending along and rotatable about a longitudinal axis generally parallel to the rotation axis, and projecting into the array of bristles.

2. The brush assembly according to claim 1, further comprising: a drive for rotating the stop element about the longitudinal axis.

3. The brush assembly according to claim 2, wherein the drive rotates the brush oppositely to the holder.

4. The brush assembly according to claim 2, wherein the drive rotates the stop at a peripheral speed at least equal to a peripheral speed of the brush holder.

5. The brush assembly according to claim 2, wherein the drive is coupled to a drive of the brush holder.

6. The brush assembly according to claim 2 wherein the drive is independent of a drive of the brush holder.

7. The brush assembly according to claim 1, wherein the stop element is provided with at least one longitudinal ridge on its outer surface.

8. The brush assembly according to claim 1, wherein the stop element is provided with a plurality of longitudinal ridges spaced angularly around its outer surface.

9. The brush assembly according to claim 8, wherein the ridges extend parallel to the longitudinal axis of the stop element.

10. The brush assembly according to claim 8, wherein the longitudinal ridges extend as spirals centered on the longtiudinal axis on the outer surface of the stop element.

11. The brush assembly according to claim 8, wherein each longitudinal ridge is of triangular section.

12. A rotary brush tool comprising: a housing; a brush holder rotatable on the housing about a rotation axis; a ring brush carried on the holder and having an annular array of radially outwardly projecting bristles; and a stop element fixed adjacent the ring brush, of noncircular section, extending along and rotatable about a longitudinal axis generally parallel to the rotation axis, and projecting into the array of bristles.

13. A method of machining a surface of a workpiece with a brush assembly having a brush holder rotatable about a rotation axis, a ring brush carried on the holder and having an annular array of radially outwardly projecting bristles, and a stop element fixed adjacent the ring brush, of noncircular section, extending along a longitudinal axis generally parallel to the rotation axis, and projecting into the array of bristles, the method comprising the step of; rotating the stop element about the longitudinal axis.

14. The method according to claim 13, wherein the stop element is rotated oppositely to a rotation direction of the ring brush and at a peripheral speed equal to or greater than a peripheral speed of the bristle array.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0023] The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

[0024] FIG. 1 is a perspective view of an embodiment of a rotary brush tool provided with a brush assembly;

[0025] FIG. 1A is a large-scale view of a detail of FIG. 1; and

[0026] FIG. 2 shows a modified version of the FIG. 1 embodiment.

SPECIFIC DESCRIPTION OF THE INVENTION

[0027] As seen in FIGS. 1 and 2 a rotary brush tool has a housing 1 and a drive 2 for a brush assembly 3 held therein. In this embodiment but not restricted to this, the brush assembly 3 has a ring brush 4, 5 formed by a brush strip 4 from which bristles extend outward.

[0028] It can be seen that the bristles 5 extend radially with respect to a rotation axis 6 and essentially project outward from a surface of the ring brush 4, 5 or a surface of the brush strip 4. The bristles 5 are U-shaped bristles 5 made of steel and fitted into and extending through mounting holes 7 in the brush strip 4 as shown in FIG. 1A. The bristles 5 form an annular array 8 with gaps 9. The ring brush 4, 5 is rotated by the drive 2 and supported by a brush holder 10, 11. In fact, the brush holder 10, 11 is formed by a ring 10 and a core 11 fitted inside it and carrying the brush strip 4 with the bristles 5. As an example, a brush holder 10, 11 can be used at this point as described in detail in US 9,554,642.

[0029] FIGS. 1 and 2 show that the brush holder 10, 11 is provided with axial webs 12 that project at the gaps 9 through the ring brush 4, 5 or the brush strip 4. In this way, overall, the brush holder 10, 11 securely rotationally secures the ring brush 4, 5 to a drive shaft 13 of the drive 2 of the rotary brush tool, so that the brush assembly 3 can be rotatably driven according to the embodiment with a counterclockwise movement around the axis 6 as shown in FIGS. 1 and 2.

[0030] A stop element 14 engaged in the rotating bristle array 8 is of particular importance. The stop element 14 is a noncylindrical pin 14 carried on an arm 15 of the housing 1 of the rotary brush tool. The stop element or pin 14 is connected parallel to the drive shaft 13 of the drive 2 or parallel to the rotation axis 6 to the arm 15. The length of the stop element 14 is selected such that it essentially corresponds to the width of the brush strip 4, consequently, the stop element 14 does not project axially with completely through the ring brush 4, 5 or only projects from it to an insignificant extent.

[0031] According to the invention, the cross section of the stop element 14 is noncircular and it rotates about its longitudinal axis 16. In fact, the cross sectionally noncircular design of the stopping aid or pin 14 in accordance with the illustrated embodiment is realized and implemented such that the stop element 14 is provided with at least one longitudinal ridge 17 on its outer surface. In this embodiment, it can be seen that a plurality of the longitudinal ridges 17 are distributed angularly around the outer surface of the stop element 14. The longitudinal ridges 17 are generally angularly equispaced over the outer surface of the stop element 14.

[0032] It can be seen that the cross section of each respective longitudinal ridge 17 is triangular. In addition, the design in the context of the embodiment according to FIG. 1 is made so that each longitudinal ridge 17 extends at this point longitudinally of the stop element 14 and consequently along the longitudinal axis 16. On the other hand, in the embodiment according to FIG. 2, the design is such that the longitudinal ridges 17 extend spirally with respect to the longitudinal direction of the stop element 14 and consequently its longitudinal axis 16. In both cases, four longitudinal ridges 17 angularly equispaced around the outer surface of the stop element 14, are not used restrictively. This means that the longitudinal ridges 17 are distributed at 90° intervals on the outer surface of the stop element or pin 14.

[0033] As already explained, the stop element 14 is rotatable in the context of the invention around its longitudinal axis 16. For this purpose, the stop element 14 has a drive shown schematically at 18 in FIG. 1. The design can be made such that the stop element 14 is driven via the drive 18 or the drive 2 inside the housing 1, and that, according to the invention, in an angular direction of rotation opposing the direction of rotation of the ring brush 4, 5. This applies explicitly to the contact area of the bristles 5 with the stop element 14. According to the embodiment, this amounts to the fact that both the ring brush 4, 5 and the stop element 14 both rotate counterclockwise. However, since the ring brush 4, 5 comes into contact with the outer surface of the stop element 14 at the ends of the bristles 5 and both rotate counterclockwise, an opposite rotation on the outer periphery. As a result, the individual bristles 5 are not only slowed down when coming into contact with the stop element 14 as in prior art, but experience an additional bending by the also provided longitudinal ridges 17. Hence, contrary to the rotation of the ring brush 4 so that the bristles 5 coming into contact with the respective longitudinal ridges 17 hit with an increased kinetic energy on a surface of a workpiece to be machined, as has already been explained above.

[0034] The drive 18 can be designed depending on the drive or the drive 2 of the brush holder 10, 11 with the ring brush 4, 5. In this case, the drive impetus of the stop element 14 is derived from that of the drive 2. For this purpose, the drive 2 may work via, for example, a toothed belt or like transmission element in the appropriate sense on the stop element 14. In general, however, the drive 18 of the stop element 14 is designed independently of the drive or the drive 2 of the brush holder 10, 11. Either way, the stop element 14 rotatably driven around its longitudinal axis 16. The peripheral speed of the stop element 14 is generally equal to or higher than the peripheral speed of the ring brush 4, 5. In this way, the surface (not expressly shown) of the workpiece (not shown) is not only provided with an increased roughness with respect to prior art, but also a uniform surface treatment is achieved. This is where the main advantages can be seen.