EP2712704B1 - Cup grinding wheel - Google Patents

Description

The invention relates to a cup grinding wheel with the features of the preamble of claim 1 and a grinding segment for a cup grinding wheel with the features of the preamble of claim 10.

Cup wheels are commonly used to abrade and polish hard surfaces such as concrete, marble, granite and other rocks, as well as to remove paint, varnish and other coatings from such base material. This is done by attaching such a cup grinding wheel to a central attachment opening of its round base disk on a portable grinder. The grinder then rotates the cup grinding wheel at the appropriate speed. The actual grinding action then regularly stirs from the attached on the surface of this base disk and projecting from her abrasive segments, which have about a diamond layer, the required hardness.

Such a cup grinding wheel, such as those from the EP 1 304 190 B1 is known, must meet various requirements. First, the grinding effect should be as strong as possible, so that a speedy and effective grinding is achieved even without strong contact pressure. Second, a uniform as possible grinding effect in the sense that even a non-uniform contact pressure of the cup grinding wheel on the surface to be ground does not lead to penetration of the cup grinding wheel in the surface to be ground at the relevant point. Third, it must also be ensured that abraded material does not deposit on the cup grinding wheel, but is moved away from it.

The realization of these and other advantageous properties depends essentially on the design and arrangement of the abrasive segments on the cup grinding wheel. Their location, cross-sectional shape, orientation, size, and other geometric properties determine how these and other goals can be achieved.

The US 2008/0176498 A1 which is considered closest to a cup wheel, shows a cup wheel with a circular one Base disk and a plurality of abrasive segments, wherein the abrasive segments each have a radially outwardly open V-shape, which V-shape is formed by two legs of the abrasive segments. The abrasive segments are arranged in pairs on a tool plate, which can be used on the base disk. The abrasive segments are relatively short in their length and relatively far apart in the circumferential direction.

The WO 2006/031044 A1 , which is considered closest to a grinding segment, shows a grinding segment for a cup grinding wheel, the grinding segment having a V-shape formed by two legs of the grinding segment and widening the legs at their diverging ends. The inner edges of the legs are arranged parallel to one another and thus form a straight, radially aligned channel.

The problem underlying the invention is therefore to further develop the known from the prior art cup grinding wheel and a grinding segment for such a cup grinding wheel so that both an improved grinding effect achieved as well as excessive contamination of the cup grinding wheel is avoided by abraded material.

The above problem is solved in a cup grinding wheel according to the preamble of claim 1 by the features of the characterizing part of claim 1 and in a grinding segment according to the preamble of claim 10 by the features of the characterizing part of claim 10.

It is essential, based on the grinding cup, the realization that the known from the prior art arrangement of the abrasive segments in the circumferential direction on the cup grinding wheel is basically useful, advantageously the arms or legs of the abrasive segments but not in a tangential direction, but rather, they are substantially radially arranged. Accordingly, with a V-shaped configuration of the abrasive segments, their respective open side is aligned in the radially outward direction. At first glance, this alignment is counterintuitive because it makes the abrasive segments seemingly transversely to the direction of rotation of the cup grinding wheel. Actually However, they are better suited. In fact, since both legs of the V-shaped grinding segments have a substantially radial extent with respect to the cup grinding wheel, they have a significantly greater abrasive effect on both of them and on the edges formed by them over this entire length. The space between the legs then allows the abraded material to detach from the surface of the abrasive segments and initially deposit in that space. Since this space is also substantially closed in the radial inner direction or at least concentrated - here the legs converge - the abraded material is pushed by the rotation at the same time in the direction of the edge of the cup grinding wheel, where it is then removed from the cup grinding wheel.

With regard to the abrasive segment itself, the effect just described is promoted in particular by the fact that the further the legs of the grinding segment move away from each other, the more the effective grinding surface of the segment increases. It has been recognized in this context that it does not depend on the size of the space between the legs, as long as a certain minimum size of this space is guaranteed. Therefore, the area between the legs, which is due to the V-shape of the abrasive segments and therefore increases in the opening direction, can be used according to the invention for the most part and with good effect for the grinding surface itself.

The preferred embodiment of the cup grinding wheel according to the invention, in particular according to claim 2, and the inventive grinding segment according to claim 11 relate to embodiments in which the space between the legs of the grinding segment is formed particularly advantageous, in particular in that it has a very good runoff of the abraded material ensured away from the cup grinding wheel from this space and in particular prevents unwanted movement of the abraded material in the direction of the center of the cup grinding wheel.

Claims 3 to 5 relating to the cup grinding wheel in turn relate to advantageous embodiments of the end region of the V shape formed by the grinding segments. By a drop-like widening of the legs of the abrasive segments towards the edge, both the grinding effect can be improved as well as a located between the leg surface of the base disk be enclosed at least laterally, which set in particular advantageous air flow conditions along the circumference of the cup grinding wheel.

Claims 5 and 6 as well as 8 and 9, which are likewise based on the cup grinding wheel, additionally provide openings in the base disk, both as cutouts at the edge and as openings spaced from the edge. These not only improve the drainage of abraded material in addition, but also increase the effective cooling of the cup grinding wheel during operation.

Further, related to the cup grinding disc claim 7 passages on the base disc, which are formed between the abrasive segments and help through their funnel-like nature to convey abraded material from inner regions of the cup grinding wheel effectively to the edge of the cup grinding wheel and from there away from the cup grinding wheel.

Finally, the preferred embodiment of the abrasive segment according to claim 13 specifically describes the lateral edges of the legs of the abrasive segments forming the V-shape.

Fig. 1

eine erste vorschlagsgemäße Topfschleifscheibe in einer Schrägansicht;

Fig. 2

dieselbe Ansicht wie in der Fig. 1 mit zusätzlicher Kenntlichmachung des Bewegungsverlaufs von abgeschliffenem Material;

Fig. 3

die vorschlagsgemäße Topfschleifscheibe der Fig. 1 in einer Draufsicht.

Fig. 4

die vorschlagsgemäße Topfschleifscheibe der Fig. 1 in einer Seitenansicht;

Fig. 5

eine weitere vorschlagsgemäße Topfschleifscheibe in einer Schrägansicht;

Fig. 6a

ein erstes vorschlagsgemäßes Schleifsegment für eine vorschlagsgemäße Topfschleifscheibe wie in der Fig. 1 in einer Schrägansicht und

Fig. 6b

das vorschlagsgemäße Schleifsegment der Fig. 6a in einer Draufsicht.

In the following, the invention will be explained in more detail with reference to a respective two embodiments of a cup grinding wheel according to the invention and a grinding segment according to the invention. In the drawing shows

Fig. 1

a first proposed Topfschleifscheibe in an oblique view;

Fig. 2

the same view as in the Fig. 1 with additional identification of the course of movement of abraded material;

Fig. 3

the proposed cup grinding wheel of Fig. 1 in a top view.

Fig. 4

the proposed cup grinding wheel of Fig. 1 in a side view;

Fig. 5

another proposed Topfschleifscheibe in an oblique view;

Fig. 6a

a first proposed abrasive segment for a proposed cup grinding wheel as in Fig. 1 in an oblique view and

Fig. 6b

the proposed abrasive segment of the Fig. 6a in a top view.

The Fig. 1 to 4 the drawing represent a first grinding wheel 1 according to the invention, which is suitable for grinding hard, especially stone surfaces. The Fig. 5 The drawing shows another cup grinding wheel 1 according to the invention, which is identical in its not explicitly described as differently described features to the first cup grinding wheel 1 according to the invention. Unless otherwise explicitly distinguished between these two cup grinding wheels 1, consequently, both cup grinding wheels 1 are equally meant.

The cup grinding wheel 1 has a substantially circular base writing 2. Furthermore, the cup wheel 1 has a plurality of abrasive segments 3. These each have a radially outwardly open V-shape, which is formed by two legs 4, 5 of the abrasive segments 3. In other words, the two legs 4, 5 of the abrasive segments 3, which correspond to the two legs of the V-shape, run in the radial direction inwardly toward one another. In the context of the present invention is meant by the radial direction always the radial direction of the cup grinding wheel 1 and thus also the base plate 2.

In the embodiments of the cup wheel 1 shown here according to the Fig. 1 to 5 For example, the V-shape of each grinding segment 3 consists of a single, integral grinding segment 3, so that the grinding segment 3 itself has this V-shape. However, it would also be conceivable that some or all of the V-shapes are formed from a multiplicity of individual abrasive segments, that is, abrasive segment sections. As a result, the V-shape would pass through multiple abrasive segments of which not every single one would necessarily be V-shaped itself. In this case, more or less large gaps could also be present between the individual grinding segment sections, which gaps are missing in the present case of the one-piece grinding segments 3. In the context of the invention, and more particularly hereinafter, the term abrasive segment 3 having a V-shape also means any group of abrasive segment sections arranged in a V-shape.

In order to realize the advantageous properties of the V-shapes for both possible directions of rotation of the cup grinding wheel 1, it is particularly preferred that the legs 4, 5 are arranged axially symmetrical to a respective axis of symmetry 6 extending in the radial direction.

It is conceivable that the legs 4, 5, which form the V-shape of the abrasive segments 3, have an opening at the respective vertex of the V-shape, that is to say a distance between the two legs 4, 5 at the vertex of the V-shape. Form exists. However, it is preferred that the respective legs 4, 5 of a grinding segment 3 in the radial direction inwardly touch.

It is also conceivable that the contact of the two legs 4, 5 takes place in the form of a cross-connection, whereby approximately in the tangential direction of the base plate 2 straight edge could be formed on the abrasive segments 3. Alternatively, it is possible that - as in the Fig. 1 to 5 illustrated in the drawing - the respective legs 4, 5 of a grinding segment 3 at a respective point of contact in the radial direction inwardly form a convex bulge 7. Such a bulge 7 prevents that at the radially inwardly facing side of this point of contact of the legs 4, 5 abraded material can accumulate.

A particularly good grinding effect can be achieved by widening the respective legs 4, 5 of a grinding segment 3 along their radial extent to the outside in the tangential direction. It is preferred that the respective legs 4, 5 widen in a drop-like manner. By a drop-like widening is here meant that the respective legs 4, 5 widened with a substantially uniform broadening rate, so not jump, and that this broadening without edges or kinks on the edge of the legs 4, 5 takes place. In this way, widened shoes 8, 9 at the respective divergent ends 4a, 5a of the legs 4, 5 are formed. The resulting widened surface of the abrasive segments 3 leads to a stronger abrasive action at the edges of the cup grinding wheel 1.

In order to achieve this good grinding action over the entire radial extent of the base disk 2, it is preferably provided that the respective legs 4, 5 of a grinding segment 3 extend in the radial direction as far as an edge of the base disk 2.

An advantageous embodiment provides that the respective legs 4, 5 of a grinding segment 3 at least partially - and preferably completely - enclose a respective edge surface 10 of the base disk 2 adjoining an edge of the base disk 2. This edge surface 10 has several technical functions. On the one hand, it forms a free space into which the material sanded off by a - in the sense of the rotational movement - first limb 4 can fall. It is thus prevented that this material affects the grinding action of the respective - depending on the direction of rotation - second leg 5. At the same time an inner edge 11a of this second leg 5 is exposed by this space. This inner edge 11a increases the grinding action of the second leg 5 compared to the hypothetical case in which a grinding segment structure between the two legs 4, 5 extends continuously in the tangential direction. Likewise, a corresponding opposite inner edge 11b of the first leg 4 is exposed.

Particularly good grinding properties result from the fact that the abrasive segment 3 forms a superficial angle β both at a point of contact of the inner edge 11a and at a point of contact of the inner edge 11b with the edge of the base plate 2. Preferably, this angle β is between 100 ° and 110 °. In particular, it can be 103 °. As a result, a course of the inner edge 11b is ensured, which ensures that abraded material is moved on this inner edge 11b in any case in the radial direction to the outside.

Finally, the edge surface 10, which is thus at least partially surrounded by the legs 4, 5, causes the cup grinding wheel to be rotated by the rotational movement 1, an increased air flow is formed around the circumference of the cup grinding wheel 1, which is suitable for removing the abraded material from the surface of the cup grinding wheel 1. In this connection, it is particularly preferred that the legs 4, 5 completely surround the edge surface 10 adjoining the edge of the base disk 2. By such a complete enclosure is meant a complete enclosure of that part of the edge surface 10 which is not already enclosed by the edge of the base disk 2 itself. In other words, in this sense, the edge surface 10 is completely enclosed by the legs 4, 5 and the edge of the base plate 2.

In order to facilitate a flow away of the abraded material from the enclosed edge surface 10 and a cooling of the cup wheel 1 is preferred and as in the Fig. 1 to 4 provided that the edge surface 10 has a respective cutout 12 of the base plate 2. A cutout 12 in this sense is a recess or opening in the base disk 2, which is open relative to the edge of the base disk 2 and in particular completely penetrates the base disk 2. In the Fig. 2 possible cutout discharge directions 13 of the abraded material are represented by the cutout 12.

Based on this, it is advantageously provided that the cutout 12 - as also in the Fig. 1 to 4 shown - is arranged substantially centrally with respect to a vertex 14 of the respective grinding segment 3 in the tangential direction.

It can also be provided that the edge surface 10 has a respective edge passage opening 12a, as in the embodiment of FIG Fig. 5 is shown. This edge passage opening 12a, which delimits itself from the cutout 12 in that it is not open to the edge of the base disk 2, can alternatively - as shown here - or be present in addition to the cutout 12. It can then replace or reinforce the drainage and cooling effects of the cutout 12.

In addition to the improved grinding behavior of the abrasive segments 3 and the facilitated outflow of the abraded material from the edge surface 10 of Base disk 2, however, the abrasive segments 3 can also be arranged so that also an improved outflow of abraded material from centrally located areas of the cup wheel 1 is achieved. For this purpose, it is proposed that between the abrasive segments 3 by respective outer edges 15, 16 of the legs 4, 5 in the radial direction funnel-like converging passages 17 are formed. The passages 17 formed in this way - which can also be referred to as funnel-like channels - between the inner region of the cup grinding wheel 1 and its edge ensure a largely residue-free outflow of abraded material from the central regions of the cup grinding wheel 1. The corresponding passage drainage direction 18 is in the Fig. 2 entered the drawing.

A particularly good outflow in this passage outlet direction 18 can be achieved, in particular, by the outer edges 15, 16 running straight at least in sections.

In this case, it is again particularly preferably provided that the outer edges 15, 16 are designed so that the straight running respective portion of the outer edges 15, 16 is arranged at an angle α to the edge of the base plate 2, which is preferably between 35 ° and 45 °. In particular, it is preferred that this angle α is 41 °. It has been found that with such an angle α, the outer edge 15 of the respective first leg 4 relative to the direction of rotation has a particularly suitable geometry for its grinding action.

An optimal outflow effect through the above-described passages 17 in turn arises from the fact that the straight running respective portions of the outer edges 15, 16 of adjacent abrasive segments 3 are arranged at an angle δ to each other, which is between 70 ° and 80 °. In particular, it is preferred that this angle δ is 72 °. This then corresponds to the opening angle of the passages 17. As from the Fig. 3 recognizable meet the imaginary extensions of said straight portions of the outer edges 15, 16 in just this angle, but at a point which lies outside the base plate 2.

It is also preferred that the straight running respective portions of the outer edges 15, 16 of a single grinding segment 3 are arranged at an angle γ to each other which is between 140 ° and 150 °. In particular, the straight portions of the outer edges 15, 16 of a single grinding segment 3, as shown in FIGS Fig. 3 shown to form an angle γ of 144 ° to each other. In this way, a good compromise is achieved, which on the one hand ensures a suitable angle of the outer edge 15 of the respective first leg 4 with respect to its grinding action and at the same time an adequate expansion of the legs 4, 5 in the radial inner direction on the base plate 2.

A further preferred embodiment of the cup grinding wheel 1 provides that the base disk 2 has an outer region 19, an inner region 20, preferably axially offset, and a transition region 21 between the outer region 19 and the inner region 20, the abrasive segments 3 being arranged in the outer region 19 , The inner region 20 regularly has the attachment opening 22, by means of which the cup grinding wheel 1 can be fastened to a grinding device. The axial return of the inner region 20 creates the possibly required space for such attachment. The oblique course of the transition region 21 prevents abraded material from sticking to the outer edge of the inner region 20. The abraded material thus flows out of the inner region 20 into the outer region 19 and from there, transported by the abrasive segment arrangement 3 away from the cup grinding wheel 1, as is likewise characterized by the throughflow direction 18.

In order to further improve the outflow of the abraded material and to additionally support the cooling of the cup grinding wheel 1, it is preferably further provided that the base plate 2 has axial passage openings 23, wherein the passage openings 23 extend at least partially into the passages 17. These through-holes 23 serve for the drainage of abraded material from both the inner region 20, as illustrated by the Durchgangsabflussrichtung 24, as well as directly from the abrasive segments 3, as the Segmentabflussrichtung 25 in the Fig. 2 is shown. Preferably, the passage openings 23 are arranged in the outer region 19.

Advantageously, the passage openings 23 are arranged in the tangential direction in each case centrally in the passages 17.

Likewise, it is preferred that the passage openings 23 are arranged at a distance from the abrasive segments 3. In other words, the passage openings 23 accordingly do not directly adjoin the outer edges 15, 16 of the legs 4, 5, but a planar part of the outer area 19 of the base plate 2 is located between the passage openings 23 and the outer edges 15, 16.

The Fig. 6a and 6b The drawing give a single inventive abrasive segment 3 for a cup grinding wheel 1 again. According to the invention, the sanding segment 3 has a V-shape which is formed by two legs 4, 5 of the sanding segment 3, the legs 4, 5 widening at their diverging ends 4a, 5a. This preferably takes place in the form of drops in the same sense as has already been described with regard to the cup grinding wheel 1 according to the invention. The diverging ends 4a, 5a of the legs are therefore those ends 4a, 5a of the legs 4, 5, which are arranged at the open end of the V-shape formed by the legs 4, 5.

Preferably, the legs 4, 5 are arranged axially symmetrically.

According to the proposal, the legs 4, 5 form a convex bulge 7 at their point of contact on an outer side 26 of the grinding segment 3. The outside 26 of the grinding segment 3 means the side of the grinding segment 3 pointing radially inward on the cup grinding wheel.

It is likewise preferred, as already described with regard to the cup grinding wheel 1, that the legs 4, 5 have outer edges 15, 16 which run straight at least in sections.

An undesired accumulation of abraded material within the concave side of a grinding segment 3 according to the invention can be avoided in particular by the fact that the legs 4, 5 a round recess 27 at form their point of contact on an inner side of the grinding segment 3. According to the above definition of the outside 26, the inside of the grinding segment 3 on the cup wheel 1 radially outward.

As has already been described in connection with the cup grinding wheel 1 according to the invention, it is also preferably provided in a grinding segment 3 according to the invention that the legs 4, 5 each have an inner edge 11a, 11b which runs straight at least in sections.

Based on this, it is particularly preferred that these inner edges 11a, 11b are arranged at an angle to the respective outer edge 15, 16 of the leg 4, 5. This is a particularly elegant way to produce the preferred drop-like broadening of the legs 4, 5 at their divergent ends 4a, 5a.

It is likewise preferred that the cup grinding wheel 1, including the grinding segments 3, has one or more rotational symmetries relative to a central axis 28.

Further preferred embodiments of the grinding segment 3 according to the invention will become apparent from the description of the cup grinding wheel 1 according to the invention.

Conversely, further preferred embodiments of the cup grinding wheel 1 according to the invention are characterized in that they have grinding segments 3 with features which correspond to the preferred embodiments of the grinding segment 3 according to the invention.

Claims (12)

1. Cup grinding wheel (1) having a substantially circular main wheel (2) and a plurality of grinding segments (3), wherein the grinding segments (3) each have a V shape that is open towards the outside in the radial direction, said V shape being formed by in each case two arms (4, 5) of the grinding segments (3), preferably wherein the arms (4, 5) are arranged in an axially symmetric manner to a respective axis of symmetry (6) extending in the radial direction, in particular wherein the respective arms (4, 5) of a grinding segment (3) are in contact towards the inside in the radial direction,
   characterized
   in that passages (17) that narrow in a funnel-like manner in the radial direction are formed between the grinding segments (3) by respective outer edges (15, 16) of the arms (4, 5).
2. Cup grinding wheel (1) according to Claim 1, characterized in that the respective arms (4, 5) of a grinding segment (3) form a convex bulge (7) towards the inside in the radial direction at a respective contact point.
3. Cup grinding wheel (1) according to Claim 1 or 2, characterized in that the respective arms (4, 5) of a grinding segment (3) widen towards the outside in the tangential direction along their radial extent, preferably in a droplet shape.
4. Cup grinding wheel (1) according to one of Claims 1 to 3, characterized in that the respective arms (4, 5) of a grinding segment (3) extend in the radial direction as far as a periphery of the main wheel (2).
5. Cup grinding wheel (1) according to one of Claims 1 to 4, characterized in that the respective arms (4, 5) of a grinding segment (3) at least partially, and preferably fully, enclose a respective peripheral surface (10), adjoining a periphery of the main wheel (2), of the main wheel (2), in particular in that the peripheral surface (10) has a respective cutout (12) in the main wheel (2), more particularly in that the cutout (12) is arranged substantially centrally in the tangential direction with respect to an apex (14) of the respective grinding segment (3).
6. Cup grinding wheel (1) according to Claim 5, characterized in that the peripheral surface (10) has a respective peripheral through-opening (12a).
7. Cup grinding wheel (1) according to one of Claims 1 to 6, characterized in that the outer edges (15, 16) extend at least sectionally in a straight manner.
8. Cup grinding wheel (1) according to Claim 7, characterized in that the main wheel (2) has an outer region (19), an inner region (20), preferably axially offset, and a transition region (21) between the outer region (19) and the inner region (20), wherein the grinding segments (3) are arranged in the outer region (19).
9. Cup grinding wheel (1) according to Claim 7 or 8, characterized in that the main wheel (2) has axial through-openings (23), wherein the through-openings (23) extend at least partially into the passages (17), wherein in particular the through-openings (23) are arranged in the outer region (19), preferably in that the through-openings (23) are each arranged centrally in the passages (17) in the tangential direction, more preferably in that the through-openings (23) are arranged at a distance from the grinding segments (3).
10. Grinding segment (3) for a cup grinding wheel (1), wherein the grinding segment (3) has a V shape which is formed by two arms (4, 5) of the grinding segment (3), and wherein the arms (4, 5) widen at their divergent ends (4a, 5a), preferably in a droplet shape,
    characterized
    in that the arms (4, 5) form a convex bulge (7) at their contact point on an outer side (26) of the grinding segment (3).
11. Grinding segment (3) according to Claim 10, characterized in that the arms (4, 5) are arranged in an axially symmetric manner.
12. Grinding segment (3) according to Claim 10 or 11, characterized in that the arms (4, 5) have outer edges (15, 16) which extend at least sectionally in a straight manner.

Images