Brush unit

Abstract

To provide a brush unit which imparts higher uniformity onto a surface of a machined workpiece than the prior art, and simultaneously increases roughness if necessary.SOLUTION: The invention concerns a brush unit (3), a rotary brush tool, and a method of machining a surface of a workpiece with the brush unit (3). The brush unit (3) has: a brush holder (10, 11) rotatably driven about a rotation axis; a ring brush (4, 5) having a bristle ring (8) having outwardly projecting bristles (5); and stop means (14) engaged in the rotating bristle ring (8). The stop means (14) with noncircular cross section is formed to be rotatable about a longitudinal axis (16) thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a brush unit having a rotatable brush holder, a ring brush having a bristle ring with outwardly protruding bristles, and a stopping means immersed in the rotating bristle ring. Similarly, the subject of the present invention is a rotary brush tool provided with such a brush unit and a method for machining the surface of a workpiece by means of said brush unit.

Background Art

[0002] In the case of a known and common brush unit of the configuration described at the beginning in the European Patent No. 1834733, an approach is made such that the bristles are braked for a predetermined time by a stopping means immersed in the rotating bristle ring. After the release of the bristles by the passage of the stopping means, the kinetic energy accumulated thereby, i.e., by the bristles and / or the brush belt holding the bristles, can be utilized. The kinetic energy is used mainly for the impact machining of the surface of the workpiece by the bristles. Thereby, an effect equivalent to that observed in so-called sandblasting is obtained. The advantage of the known approach described in the European Patent No. 1834733 over sandblasting is that the work is done without a blasting material, whereby the equipment-technical costs are significantly reduced compared thereto. Environmental pollution by the blasting material can also be avoided. In addition, a particularly inexpensive configuration and an efficient approach are recognized. This has been proven to be effective.

[0003] In another common prior art described in International Publication No. 2012038537, an approach is taken in which a stopping means immersed in a rotating bristle ring is simultaneously formed as an abrasive for the bristle. In this case, the two functions, namely the stopping function and the abrasive function, can be distinguished depending on the rotational direction of the ring brush and / or the adjustment position of the stopping means relative to the bristle ring. Thus, in practice, the stopping means is formed to be adjustable relative to the bristle ring. In this case, the adjustment of the stopping means is performed radially and / or tangentially. Eccentric adjustment of the stopping means is also possible. In addition, the stopping means can be adjusted by the driven bristle.

[0004] Conventional techniques have proven effective in terms of surface treatment of workpieces using bristle and the resulting roughness. However, with previous approaches, the workpiece surface may not consistently and uniformly have the "craters" induced by bristle. While it is true that a configurable roughness comparable to sandblasting can be achieved, thereby enabling subsequent coating and welding processes on the workpiece surface without problems, the roughness profile is subject to variation; that is, conventional techniques exhibit a certain degree of anisotropy. However, for many applications, isotropic and uniform roughness on the treated workpiece surface is required.

[0005] The anisotropy or lack of uniformity in the roughness profile observed in prior art is essentially due to the fact that the bristle is typically fixed to a brush belt. Since the bristle is also often formed as a U-shaped bristle, the brush belt supporting the bristle has rows of bristles and axial spacing between them in its circumferential direction, which contribute, for example, to the U-shape of the bristle. The spacing between individual rows of bristle causes the roughness profile to be formed unevenly during impact machining of the workpiece surface. In practice, attempts have certainly been made to address this by having the user move the brush unit or a rotary brush tool equipped with this brush unit back and forth, for example, across the surface.

[0006] Aside from the fact that such movement is cumbersome and does not necessarily contribute to the required uniformity, such an approach cannot be directly implemented, for example, when mechanically processing the surface of a workpiece by a machine, such as a robotic arm. Furthermore, the prior art requires more effective processing of the workpiece surface. Herein, the present invention intends to address this as a whole. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] European Patent No. 1834733 [Patent Document 2] International Publication No. 2012038537 Brochure [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The fundamental technical challenge of this invention is to develop such a brush unit so that the resulting roughness profile has improved uniformity on the surface of the processed workpiece compared to conventional techniques. In addition, the possibility of increasing the roughness as needed should also be maintained. [Means for solving the problem]

[0009] To solve this technical problem, the present invention proposes that in a general brush unit within the scope of the present invention, a stopping means having a non-circular cross-section is formed to be rotatable about its vertical axis.

[0010] That is, within the scope of the present invention, firstly, a stopping means that is immersed in a special, rotating bristle ring, i.e., such a stopping means having a non-circular cross-section, is applied. This means that the stopping means has a cross-section other than a circular or circular cross-section. The cross-section can be formed, for example, angular or polygonal. That is, in the prior art, the stopping means is mainly formed as a cylindrical pin, but the present invention operates with a prism-like stopping means having a non-cylindrical, so-called non-circular cross-section. In fact, for this purpose, the stopping means usually has at least one longitudinal web around it. This longitudinal web can be advantageously formed triangular in cross-section.

[0011] As a result, in relation to the fact that the stopping means is additionally formed to be rotatable about its longitudinal axis and has a drive mechanism in connection therewith, the overall roughness profile thus generated is significantly more uniform than in the prior art. Another particular advantage is the improved roughness.

[0012] In fact, the drive mechanism for the stopping means can be designed to be subordinate to or independent of the drive mechanism for the brush holder having the ring brush.

[0013] In the former case, the stopping mechanism is driven via the drive of the brush holder, which in turn acts on the stopping mechanism, for example, via a direction change unit and possibly an additional gear unit, causing the stopping mechanism to rotate around its longitudinal axis. However, generally, an approach is taken in which the drive device for the stopping mechanism is designed independently of the drive device for the brush holder having the ring brush. In this case, a separate and dedicated drive device is provided for the stopping mechanism.

[0014] Furthermore, the design typically involves the stopping mechanism rotating circumferentially, opposite to that of the ring brush. In this case, the effectiveness has been proven when the stopping mechanism rotates at the same or a higher circumferential speed than that of the ring brush.

[0015] In this way, firstly, it is achieved that the stopping means does not only brake the individual bristle that moves against the driving of the ring brush by at least one of its longitudinal webs or based on the formation of a non-circular cross-section. Moreover, the non-circular formation of the stopping means or the longitudinal web, which is usually provided in this case, with a triangular cross-section, in connection therewith, contribute to the bending back of each bristle that strikes the longitudinal web, first in the opposite direction of its driving. That is, the bristle is braked by the stopping means during its rotation, as is well known and basically described in detail in the prior art. The stopping means or the non-circular formation of the longitudinal web additionally contribute to the further bending back of the bristle.

[0016] As a result, the additionally bent bristle strikes the workpiece surface to be machined with higher impact energy compared to the bristle struck by the stopping mechanism in areas where the longitudinal web is absent. In this way, a more enhanced surface machining of the workpiece is observed compared to the prior art. In addition, the rotation of the stopping mechanism in the opposite direction to that of the ring brush contributes to each rotation of the stopping mechanism corresponding to a different roughness.

[0017] Bristels that are additionally bent back by the longitudinal web produce particularly deep craters, which are not the case for bristels that do not come into contact with the longitudinal web. These different crater depths observed around the rotating stopper not only result in a higher overall roughness of the surface of the workpiece thus processed compared to the prior art, but also result in an additional uniformity of the roughness profile. This may be due to the fact that the bristels, which are still generally spaced apart from each other and fixed to the brush belt in longitudinal rows, are still spaced apart from each other. However, the different bending stresses of the bristels during rotation cause them to bend laterally in part, thus eliminating areas of the workpiece surface that are not processed at all or only slightly processed. This is, of course, also due to the fact that the bristels are generally spaced only a few millimeters apart from each other, and the brush belt, by its design, usually provides the necessary restoring force for the bristels as a woven belt. For further details, see the description in European Patent No. 1834733.

[0018] In another advantageous configuration, the stopping means not only has at least one longitudinal web around it, but generally multiple longitudinal webs are realized and provided distributed and arranged around the stopping means. In this case, the longitudinal webs have the same angular spacing and are distributed and arranged around the stopping means taking this same angular spacing into consideration. In this case, the design is additionally made such that each longitudinal web extends longitudinally around the stopping means, so that all the bristle of the ring brush is braked or additionally bent back by the stopping means or its longitudinal webs as described.

[0019] A particularly important embodiment further features that each longitudinal web extends helically with respect to the longitudinal direction or longitudinal axis of the stopping means. The helical arrangement of the longitudinal webs relative to the longitudinal direction or longitudinal axis of the stopping means causes the bristle connected to the brush belt to be additionally bent back by the longitudinal web, for example, within the same radial spread when viewed axially. Rather, only each individual bristle is additionally bent back by the stopping means in the opposite direction to the ring brush, which results in a further improved uniformity of the surface roughness profile of the workpiece. This is because, when the bristle strikes the stopping means, the brush belt supporting the bristle is no longer deformed axially, so to speak, as intended by the bristle, and this deformation differs along the axial direction, which causes a very slight additional lateral movement of the bristle, and thus covers the remaining gaps between the individual bristle. In other words, there are no longer any areas on the surface of the workpiece that are not treated at all or only slightly treated, and overall, the roughness is significantly more uniform than in the prior art.

[0020] In this case, the rotation of the stopping means in the opposite direction to that of the ring brush ensures, as a whole, that the bristle, which strikes each longitudinal web, is additionally bent back. In this case, the present invention is also based on the recognition that the bristle usually has an angled end that strikes one or more longitudinal webs. In this case, the angle of the bristle follows the rotational motion of the ring brush.

[0021] As a result, a brush unit is provided which acts with specially designed stopping means, which normally rotates in the circumferential direction contrary to the ring brush (in the contact area) and, based on its characteristic of having a non-circular cross-section, contributes to the bristles deflecting differently when hitting the stopping means. This changing deflection of the bristles and the different kinetic energies associated with it contribute not only to the machining of the surface of the workpiece with improved roughness, but in particular to the roughness profile being homogenized. This of course applies not only to the brush unit according to claim 1, but equally and independently of this, to the rotary brush tool according to claim 12 and to the method for machining the surface of the workpiece according to independent claims 13 and 14. Here, an important advantage can be seen.

[0022] Hereinafter, the present invention will be described in more detail by means of the drawings showing only one embodiment.

Brief Description of the Drawings

[0023] [Figure 1] Perspective view of a first embodiment of a rotary brush tool provided with a brush unit [Figure 2] Implementation variations with modifications of the object according to FIG. 1

Modes for Carrying Out the Invention

[0024] The figure shows a rotary brush tool comprising a machine housing 1 and a drive unit 2 for a brush unit 3 housed in the machine housing, which is only shown implicitly. The brush unit 3 has ring brushes 4, 5, which in this example and not by way of limitation consist of a brush belt 4 and bristles 5 connected to this belt and protruding outwards.

[0025] The bristle 5 extends radially relative to the rotation axis 6 and is observed to be substantially upright on the surface of the ring brushes 4,5 or the surface of the brush belt 4. The bristle 5 is a U-shaped bristle made of steel, and these bristles are inserted into and passed through the merely implicitly indicated receiving holes 7 in the brush belt 4, as can be understood from the clip in Figure 1. The bristle 5 forms a bristle ring 8 with an interrupted portion 9. The ring brushes 4,5 are rotationally driven by the drive unit 2 and supported by brush holders 10,11. In practice, the brush holders 10,11 consist of a ring 10 and an insert 11 that is insertable into the ring and supports the brush belt 4 having the bristle 5. Exemplary, brush holders 10,11 as described in detail in European Patent No. 1834733 may be used here.

[0026] Figures 1 and 2 show that the brush holders 10 and 11 are each equipped with an axial web 12 that grips the ring brushes 4 and 5 or the brush belt 4 within the region of the interrupted section 9. In this way, the brush holders 10 and 11 as a whole contribute to the secure holding of the ring brushes 4 and 5 on the drive pin 13 of the drive unit 2 of the rotary brush tool, and this drive pin causes the brush unit 3 to rotate in a counterclockwise motion about the rotation axis 6 shown in Figures 1 and 2 according to this embodiment.

[0027] Of particular importance to the present invention is the stopping means 14 that is immersed in the rotating bristle ring 8. The stopping means 14 is a cylindrical pin 14 connected to the mechanical housing 1 of the rotating brush tool via an arm 15. In this case, the stopping means 14 or pin 14 is connected to the arm 15 parallel to the drive pin 13 of the drive unit 2 or parallel to the rotation axis 6. In this case, the length of the stopping means 14 is selected to substantially match the width of the brush belt 4, so that the stopping means 14 protrudes little to no in the axial direction relative to the ring brushes 4, 5.

[0028] According to the present invention, the stopping means 14 has a non-circular cross-section and rotates about its longitudinal axis 16. In practice, the non-circular cross-section of the stopping means or pin 14 according to this embodiment is realized such that the stopping means 14 has at least one longitudinal web 17 around it. From this embodiment, it can be seen that there are multiple longitudinal webs 17 distributed around the stopping means 14. In this case, the longitudinal webs 17 are generally distributed around the stopping means 14 at the same angular intervals.

[0029] It can be observed that each longitudinal web 17 has a triangular cross-section. In addition, the design, within the scope of the embodiment shown in Figure 1, extends each longitudinal web 17 in the longitudinal direction of the stopping means 14, and therefore along the longitudinal axis 16. In contrast, in the embodiment shown in Figure 2, the design is carried out so that each longitudinal web 17 extends spirally in the longitudinal direction of the stopping means 14, and therefore relative to its longitudinal axis 16. In both cases, work is carried out to have four longitudinal webs 17 that are uniformly distributed around the stopping means 14, although this is not limited to the case. That is, the longitudinal webs 17 are distributed around the stopping means or pin 14 at 90° intervals.

[0030] As already described, the stopping means 14 is formed to be rotatable about its longitudinal axis 16 within the scope of the present invention. For this purpose, the stopping means 14 has a drive device 18, which is only implicitly shown in Figure 1. In this case, the design can be made such that the stopping means 14 is driven via a drive device or drive unit 2 within the machine housing 1, and according to the present invention, in a circumferential rotational direction opposite to the rotational direction of the ring brushes 4, 5. This obviously applies to the contact area between the stopping means 14 and the bristle 5. This means that, according to this embodiment, both the ring brushes 4, 5 and the stopping means 14 rotate counterclockwise. However, since the ring brushes 4, 5 contact the circumferential side of the stopping means 14 with their bristle 5, and both rotate counterclockwise, opposite motions occur on the circumferential side. As a result, each bristle 5, upon impact with the stopping means 14, is not only braked as in the prior art, but also subjected to additional bending back by the additionally provided longitudinal webs 17, i.e., in the opposite direction to the rotation of the ring brush 4. Therefore, each bristle 5 that strikes the longitudinal web 17 strikes the surface of the workpiece to be processed with high kinetic energy, as already described.

[0031] The drive unit 18 can be designed to be subordinate to the drive unit or drive unit 2 of the brush holders 10 and 11 having ring brushes 4 and 5. In this case, the driving motion of the stopping means 14 is derived from the driving motion of the drive unit 2. However, generally, the drive unit 18 of the stopping means 14 is designed to be independent of the drive unit or drive unit 2 of the brush holders 10 and 11. In any case, the stopping means 14 is rotationally driven about its longitudinal axis 16. In this case, the peripheral speed of the stopping means 14 is generally designed to be the same as or higher than the peripheral speed of the ring brushes 4 and 5. In this way, the surface of the workpiece not explicitly shown not only has improved roughness compared to the prior art, but also achieves a relatively uniform surface finish. Herein lies a significant advantage.

Claims

1. A brush unit having a rotatable brush holder (10, 11), a ring brush (4, 5) having a bristle ring (8) with outwardly protruding bristles (5), and a stop means (14) recessed in the rotating bristle ring (8), A brush unit characterized in that a stop means (14) having a non-circular cross section is formed so as to be rotatable about its longitudinal axis (16).

2. 2. A brush unit (3) according to claim 1, characterized in that the stopping means (14) comprise a drive (18).

3. 3. The brush unit (3) according to claim 2, characterized in that the drive device (18) of the stopping means (14) is formed subordinate to or independent of the drive device (2) of the brush holder (10, 11) having the ring brushes (4, 5).

4. 4. The brush unit (3) according to claim 1, wherein the stopping means (14) rotates in a circumferential direction opposite to that of the ring brushes (4, 5).

5. 5. Brush unit (3) according to claim 4, characterized in that the stopping means (14) rotate at the same or higher peripheral speed than the ring brushes (4, 5).

6. 2. Brush unit (3) according to claim 1, characterized in that the stop means (14) comprises at least one longitudinal web (17) around its periphery.

7. 7. Brush unit (3) according to claim 6, characterized in that the stop means (14) is provided with a plurality of longitudinal webs (17) distributed over the periphery thereof.

8. 8. Brush unit (3) according to claim 6 or 7, characterized in that the longitudinal webs (17) are arranged distributed over the periphery of the stop means (14) at equal angular intervals.

9. 8. Brush unit (3) according to claim 6 or 7, characterized in that each longitudinal web (17) extends in the longitudinal direction of the stop means (14).

10. 8. Brush unit (3) according to claim 6 or 7, characterized in that each longitudinal web (17) extends helically relative to the longitudinal direction of the stop means (14).

11. 8. Brush unit (3) according to claim 6 or 7, characterized in that each longitudinal web (17) is formed with a triangular cross section.

12. A rotary brush tool comprising a machine housing (1), a brush unit (3), and a drive (2) for the brush unit (3), wherein the brush unit (3) comprises rotatably driven brush holders (10, 11), ring brushes (4, 5) having a bristle ring (8) with outwardly protruding bristles (5), and a stop means (14) that is recessed in the rotating bristle ring (8), A rotary brush tool characterized in that the stop means (14) is formed non-circular in cross section and is rotatable about its longitudinal axis (16).

13. A method for processing the surface of a workpiece by means of a brush unit (3) having a rotatably drivable brush holder (10, 11), a ring brush (4, 5) having a bristle ring (8) with outwardly projecting bristles (5), and a stop means (14) that is recessed in the rotating bristle ring (8), comprising: The method is characterized in that the stop means (14) rotates about its longitudinal axis (16).

14. 14. Method according to claim 13, characterized in that the stopping means (14) rotate in a circumferential direction opposite to the ring brushes (4, 5) and preferably at the same or higher circumferential speed relative to the ring brushes (4, 5).

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