EP1894692A1 - Tool for cutting natural and composite stone - Google Patents

Abstract

The tool has a carrier plate to be moved for machining operation in rotary motion. A cutting edge (20) is formed at the carrier plate, and has cutting segments (30) arranged at the carrier plate. The cutting segments are made of a carbide base and a polycrystalline diamond layer, and have the form of cylinder segments. The segments are arranged at the carrier plate in such a manner that a working edge operating in a rotational direction is formed through two edges of the segments, where the edges limit the polycrystalline diamond layer and meet in a segment angle.

Description

Technical area

The invention relates to a tool for cutting en natural and artificial stone, comprising a to be offset for a machining operation in a rotational movement carrier, wherein on the carrier a cutting edge is formed, which comprises a plurality of arranged on the carrier cutting segments, which consists of a sintered carbide Carrier material and a layer of polycrystalline diamond exist. The invention further relates to a hand-held device for cutting natural and artificial stone.

State of the art

Tools for cutting natural and artificial stone are well known. In particular, cutting wheels are used for producing straight cuts, ie tools in the form of a circular plate, on whose circumference a cutting edge is formed and / or cutting elements are fastened. For producing larger cylindrical bores also drill bits are used, which are formed as a hollow cylinder, at its free end in turn a cutting edge is formed and / or cutting elements are attached.

Recently cutting elements with diamond materials, in particular polycrystalline diamond (PCD), are increasingly being used for cutting natural or artificial stone:

The EP 1 004 414 A2 (F. Neher ) shows, for example, a blade-like tool for machining stone or stone-like materials, which is equipped with cutting cuboid PCD segments. The segments are used in stepped recesses in the edge region of the tool and preferably at a negative angle to the direction of rotation of the tool.

The EP 1 369 195 A (Hilti ) relates to a coring bit for machining brittle materials such as concrete or masonry. The drill bit comprises flat cuboid cutting elements with frontal cutting edges. Two cutting elements differ in terms of their axial and / or Radialspanwinkel, or there is at least one cutting element with a non-zero radial rake angle available. The cutting elements are preferably formed as PCD elements.

The EP 0 846 537 A2 (0th hall ) describes a tool for separating materials such. As stone or concrete, with a cutting segment carrier made of steel, are attached to which cutting segments. These consist of a sintered material in which diamonds are embedded. The cut surfaces are formed by the end faces of the cutting segments; the segments are soldered to a base surface parallel to the end face on a holding surface of the cutting segment carrier. The tool can as Drill bit or be designed as a saw blade. In order to minimize the thermal stress on the cutting segments, their cutting surfaces are inclined to the direction of the cutting movement by an angle of 15-45 °, so that the cut surfaces accumulate on the material to be cut. The holding surfaces on the cutting segment carrier are, for example, sawtooth-like incorporated in the outer peripheral surface of the segment carrier of a drill bit or a saw blade. The cutting segments are essentially cuboid.

It has been found that there is room for improvement based on the known tools for cutting natural and artificial stone with regard to lifetime cutting performance and / or cutting quality.

Presentation of the invention

The object of the invention is to provide a tool belonging to the aforementioned technical field, which has a long service life and enables high cutting performance with good cutting quality.

The solution of the problem is defined by the features of claim 1. According to the invention, the cutting segments are substantially in the shape of a cylinder segment and are arranged on the carrier such that a forward working edge is formed by two edges of the cutting segment which meet at a segment angle and which define the polycrystalline diamond layer.

It has surprisingly been found that in the inventive, specific training and arrangement of the cutting segments a very efficient cutting of natural and artificial stone is possible. With the inventive tool, a high operating speed and a good quality of cut can be achieved. It is - in the appropriate size - for both handheld devices (such as cutters, Flex), for stationary devices (such as stationary concrete cutters, table saws), as well as for mobile stand devices (such as wall saws) suitable. Due to the robust construction and the hardness of the working edge, the tool is very stable. The durability of the tool is also based on its simple construction: Because the cutting segments are so durable that an exchange the same is not necessary, they can be directly and permanently attached to the carrier, there are no additional support elements needed.

The tool is suitable for use in commercially available devices (angle grinders, flex, concrete cutters, wall saws, etc.), in particular as a replacement for conventional cutting discs, saw blades or drill bits. Particularly suitable is the tool for cutting reinforced or non-reinforced concrete.

Advantageously, at least four, preferably sixteen or more, cutting segments are arranged along the cutting edge at regular angular intervals. By using multiple cutting segments, a high work efficiency is achieved, and it results in a uniform operation.

The segment angle is advantageously 25-90 °, preferably about 40-50 °. It has been found that at such angles, there is an optimum combination of mechanical robustness with work efficiency. At angles smaller than 25 °, a reduced mechanical stability of the tool results. At angles greater than 90 °, the processing efficiency and the quality of the cut decrease.

For the application according to the invention particularly suitable cylinder segments have in particular the shape of a hatchback (segment angle about 45 °), a radius of 4-10 mm, in particular 5-8 mm, and an axial extent of 5 -12 mm, in particular 6 - 10 mm , The arrangement of 10 to 30, in particular 15 to 20, PCD cutting segments per meter circumference of the cutting edge has proved to be particularly suitable for particularly efficient work.

Preferably, the straight edges of the cutting segments which meet at the segment angle span a plane which is inclined against the direction of rotation and encloses an angle of 45-97 °, preferably 70-90 °, in particular approximately 75-85 °, with a tangential to the cutting edge , the working edge is thus oriented at a negative angle to the direction of rotation of the tool. The angled arrangement ensures that the portion of the cutting edge which is the farthest away from the carrier and which first comes into contact with the material to be processed in a surface treatment is arranged at the rear in the direction of rotation of the carrier, while the portion adjoining the carrier Section of the cutting edge in the direction of rotation vorderst lies. It results in a uniform working resistance and a uniform machining. The specified angles allow the best possible working efficiency, secure attachment of the cutting segments on the support plate and a direct dissipation of adverse forces in the carrier.

Depending on the desired processing, it is in principle also possible to arrange the cutting segment with its cylinder axis parallel to the respective tangents of the carrier or to choose a larger angle.

For attachment to the carrier, the cutting segments are advantageously arranged in cutouts of an edge region of the carrier, the two meeting, the working edge forming edges of the cutting segments at least partially projecting beyond an edge of the carrier. The cut-outs allow secure attachment of the cutting segments to the carrier. By a corresponding geometry of the cutouts, the cutting segments can be easily mounted inclined to the carrier. Because the carrier partially surrounds the cutting segments and thus lies partially behind the active working surface bounded by the edges forming the cutting edge, it contributes to good guidance of the tool during machining and thus to easier handling of the tool.

Alternatively, the cutting segments are fastened with their lower side on a substantially circular border of the carrier.

Each of the cutting segments preferably contacts at least partially a wall of the respective cutout, both with an end face that is substantially triangular in the direction of rotation, and with an opposite, essentially triangular face. There is thus a positive and therefore permanent connection between the cutting segment and the carrier in the working direction. Forces can be transmitted directly from the cutting segment to the carrier.

Preferably, the cutting segments are also attached over a large area in the respective cutout of the carrier, in particular soldered. Large area means that the cutting segment is not only point or line connected to the carrier, but that there is a flat connection point; the cutting segment contacted, for example with a substantial part of its cylinder surface the bottom of the cutout. The corresponding geometry also results in a mechanical, positive support of the cutting segment in the cutout and thus an improved transmission of counter forces occurring during the machining process.

Advantageously, the edge region of the carrier made of tool steel and tapering towards the outside is formed. The shape of the edge is thus adapted to the tapered shape of the cutting segments and thus enables a stable attachment of the segments in the lower region, without that the processing, which takes place primarily through the upper region, is disturbed. The edge region of tool steel is - as the cutting segment - partially removed in the course of use of the tool, so that the supernatant of the cutting segments remains essentially unchanged.

The extent to which the edge area is removed can be influenced by its dimensioning. If the removal of the cutting segments is higher than that of the edge region and if the edge region is not designed to be weaker for mechanical reasons, conventional steel-based segments can additionally be arranged in the region of the cutting edge on the carrier between the PCD cutting segments.

Advantageously, the edge region comprises a plurality of spaced-apart sector-like sections. The cutouts for receiving the cutting segments are arranged in the sector-like sections. For example, a toothing can be provided between the individual sections. This improves the cooling of the tool and increases the possible depth of cut.

The cutting segments are advantageously arranged within the respective sector-like sections. For example, one cutting segment may be provided centrally per section, or a plurality of segments distributed uniformly per section may be provided.

Preferably, the working edge is chamfered. As a result, the risk of breakage for the PCD layer of the cutting segment can be significantly reduced and the service life of the tool can be increased accordingly.

Advantageously, the ratio between the axial extent of the cutting segment (ie the height of the corresponding cylinder) and the radius of the cutting segment is at least 0.8, preferably at least 1.0. Thus, the cutting segment is not merely a disk-like "blade", but a solid body over which the opposing forces occurring during the machining process can be reliably dissipated to the carrier plate. The corresponding cylinder segment can also be securely fastened to the carrier plate and has a high mechanical stability.

The thickness of the layer of polycrystalline diamond (PCD) measured in the axial direction is advantageously at least 0.8 mm, preferably at least 1.2 mm. It is thus not just a PCD coating on a hard metal body, but a sintered on the support body PCD block. This ensures a long service life, ensures that the cutting edges are always formed completely from the PCD material even after prolonged use and that the cooperating with the material to be machined surface of the cutting segments always has such a smoothness that removed material not at the cutting segments adheres.

Preferably, the cutting segment is mounted on the carrier in such a way that the straight edges, which form the working edge, are arranged symmetrically to the cutting edge. Correspondingly, the counterforces acting on the cutting segment can be passed on to the carrier, regardless of their direction, and both edges, which form the working edge of the cutting segment, are equally loaded in the time average. The said arrangement also allows efficient and accurate work.

For certain applications, the cutting segment may also be arranged such that the two straight edges are asymmetrical with respect to the cutting edge, i. H. that during machining the two straight edges act differently on the machined material.

The carrier may be a substantially circular cylindrical disc, wherein the cutting edge is formed on the circumference of the disc. The tool thus acts in the manner of a cutting disc and serves primarily to produce straight running cuts.

The thickness of the disc is advantageously at least 3 mm, in particular about 4 - 5 mm. Depending on the application, the disc can be manufactured with a diameter of 100-400 mm for hand tools, 250 - 500 mm for stationary devices and 600 - 1'800 mm for wall saws.

The carrier may also be designed as a substantially circular cylindrical drill bit, wherein the cutting edge is formed at a free end of the drill bit. The corresponding tool thus serves to produce cylindrical cuts or holes. The thickness of the cylinder jacket is again advantageously at least 3 mm, in particular approximately 4 mm, the diameter of the drill bit can be between 10 and 60 cm.

From the following detailed description and the totality of the claims, further advantageous embodiments and feature combinations of the invention result.

Brief description of the drawings

Fig. 1A

Eine Draufsicht auf eine erste Ausführungsform eines erfindungsgemässen Werkzeugs;

Fig. 1 B

eine Seitenansicht des Werkzeugs;

Fig. 2

eine detaillierte Schrägansicht der Schneidkante des Werkzeugs;

Fig. 3

einen Querschnitt durch die Schneidkante;

Fig. 4

ein Schneidsegment des erfindungsgemässen Werkzeugs in einer Schrägansicht;

Fig. 5

eine Draufsicht auf eine zweite Ausführungsform eines erfindungsgemässen Werkzeugs; und

Fig. 6

eine Draufsicht auf eine dritte Ausführungsform eines erfindungsgemässen Werkzeugs.

The drawings used to explain the embodiment show:

Fig. 1A

A plan view of a first embodiment of an inventive tool;

Fig. 1 B

a side view of the tool;

Fig. 2

a detailed oblique view of the cutting edge of the tool;

Fig. 3

a cross section through the cutting edge;

Fig. 4

a cutting segment of the inventive tool in an oblique view;

Fig. 5

a plan view of a second embodiment of an inventive tool; and

Fig. 6

a plan view of a third embodiment of an inventive tool.

Basically, the same parts are provided with the same reference numerals in the figures.

Ways to carry out the invention

FIG. 1A shows a plan view of a first embodiment of a tool according to the invention; Figure 1 B shows a side view of the tool. The tool 1 comprises a solid circular support plate 10 made of tool steel with a thickness of about 5 mm and an outer diameter of 700 mm. The support plate 10 is flat, its thickness is constant except for the edge region. In the region of the center of the support plate 10, a series of openings 11 for fixing the tool 1 in a commercial wall saw are formed symmetrically to the center thereof.

On the circumference of the tool 1 of the cutting edge 20 forming edge portion 21 of the support plate 10 is divided into 40 sector-like sections 22, each having a length of about 40 mm. Each of these sections 22 carries a respective cutting segment 30. Between two adjacent sections 22 in each case a substantially radially not inwardly extending incision 23 is formed in the support plate 10. The cutting edge 20 with the sector-like sections 22 of the edge region 21, the cutting segments 30 and the notches 23 is shown in detail in an oblique view in FIG. 2, FIG. 3 shows a cross section through the cutting edge 20.

In the region of the sector-like sections 22, the edge region 21 of the carrier plate 10 is configured to taper outwardly symmetrically on both sides. In a cross-section extending radially perpendicular to the main surface of the carrier plate 10, the edge region 21 has essentially the shape of an isosceles triangle, wherein the outer edge 22a forming the circumference of the carrier plate 10 is rounded. The angle β between the flank 22b of the portion 22 and the main surface of the support plate 10 is about 25 °, the radial extent of the portion 22 thus about 4.3 mm.

As mentioned above, in each case an incision 23 is formed in the carrier plate 10 between in each case two adjacent sections 22 of the edge region 21. The notch 23 comprises a radially extending channel 23a with a constant cross section and a circular hole 23b which adjoins the channel 23a on the inside. The width of the channel 23a is about 3.5 mm, the diameter of the hole 23b about 6.5 mm. The cuts 23 thus form a known close keyhole teeth which simultaneously allows a clean cut, a quiet running of the tool and a good cooling and thus large cutting depths. Between the longitudinal ends of the sector-like sections 22 and the mouth of the channel 23a each recessed transition portions 21a are each formed with a length of approximately 5.5 mm relative to the outer edge 22a.

Centered in each sector-like section 22 is a cutting segment 30. This is shown in detail in FIG. 4 in an oblique view. The cutting segment 30 has the shape of a circular cylinder segment with a segment angle α of 45 ° (so it is an eighth cylinder). The height H of the cutting segment is about 8 mm, its radius r is about 6.5 mm. The cutting segment 30 is formed by a carrier body 31 made of tungsten carbide, on which a portion 32 of polycrystalline diamond (PCD) is sintered as a whole. The total thickness h of the PCD section 32 is about 2 mm.

The end face 33 delimiting edges 34a, 34b of the section 32 of polycrystalline diamond form the working edge 35 of the cutting segment 30. These edges 34a, 34b and the other end face 33 limiting, circular section-shaped edge 34c are chamfered at an angle of 45 °, the width the chamfer is 0.5 mm each.

Surprisingly, cutting segments 30 have proven to be particularly suitable which are made of commercially available blanks "Syndrill® RSI-R" from Element Six Ltd. getting produced. These blanks are themselves intended as inserts for deep hole drilling tools in the oil and gas industry which are used to remove soft to medium abrasive rock. The blanks consist of a section of polycrystalline diamond, which as a whole is sintered in a high-pressure and high-temperature synthesis process on a one-piece body made of tungsten carbide. The diamond grain size is 20 - 40 microns, the tungsten carbide substrate has a grain size from 3 to 6 μm and a cobalt content of 13% by weight. A particular advantage of this material is the fact that the sharp cutting edge is retained in the PCD section even after removal of this section. The support body also forms a rigid and durable base for the PCD section and allows the production of a permanent solder joint with a base body (ie in the present case with the support plate 10). The syndrome blanks are cylindrical, by spark erosion they can be cut into several directly usable as cutting segments 30 cylinder segments.

The cutting segments 30 are mounted in circumferential recesses 24 of the sector-like sections 22. The recesses have a part-cylindrical bottom 24a, thus can be easily cut into the sections 22 with cylindrical tools. The (imaginary) cylinder axis of the recess 24 extends at an angle of approximately 20 ° to the respective tangents of the support plate 10. The cylinder radius substantially corresponds to the radius r of the male cutting segment 30. Against the direction of rotation increases the depth of the recess 24 and close at its rear end in the direction of rotation its maximum. The rear end surface of the recess 24 is flat and extends at an angle of 90 ° to the bottom of the recess 24th

The cutting segment 30 can thus be suitably received by the recess 24, wherein the depth and the length of the recess 24 are selected such that the cutting segment 30 projects in its widest region by about 0.5 mm laterally beyond the support plate 10 and that the Cutting segment 30 with its front end face 33 as well as with its rear end face 36 a corresponding planar contact surface 24b, 24c of the recess 24 contacted flat. The cutting segment 30 is thus held positively between these contact surfaces 24b, 24c and the bottom 24a. The cutting segments 30 are also soldered in the recesses 24 by means of an induction soldering process.

Lateral and radial over the sector-like portion 22 of the edge portion 21 of the support plate 10 also protrude substantially the two straight edges 34a, 34b of the frontal PCD portion 32 and the underlying parts of the PCD portion 32 and the support body 31. The meeting point of the straight Edges 34a, 34b of the frontal PCD portion 32 forms the radially outermost element of the tool 1, from the outer Edge 22a of the respective sector-like portion 22, it has a distance of about 3 mm. The cutting segment 30 is received symmetrically in the recess 15 such that the two edges 34a, 34b enclose the same angle with the main surface of the carrier plate 10. The arranged in the direction of rotation front edges 34a, 34b of the front side PCD portion 22 together form the primary cooperating with the material to be machined working edge 35 of the cutting segment 30th

Figures 5 and 6 each show a partial plan view of a second and a third embodiment of a tool according to the invention: The type, configuration and number of cutting segments used can be adapted to the processing purpose. The same applies to the dimensions of the carrier plate (diameter, thickness). As an example, FIG. 5 shows a tool 101 with a carrier plate 110 with a diameter of 350 mm, which is suitable, for example, as a cutting disk for a hand-held device. On the circumference of the support plate 110 twenty sector-like sections 122, each with a cutting segment 130 are arranged at a uniform angular distance. In turn, recesses 123 are formed in the carrier plate 110 between the sector-like sections 122. These are wider than the cuts of the first embodiment. They include a radially inwardly slightly tapering channel 123a and an inside of the channel 123a subsequent drop-shaped hole 123b. Together, the notches 123 form a slightly wider toothing compared to the first embodiment. This allows a good cooling and a high depth of cut in softer material.

Otherwise, the structure of the tool 101 corresponds to that of the tool 1, which has been described above in connection with FIGS. 1-4.

As a further example, FIG. 6 shows a tool 201 with a carrier plate of 350 mm diameter, wherein along the circumference ten sector-like sections 222 each having three cutting segments 230.1, 230.2, 230.3 are arranged. The two outer cutting segments 230.1, 230.3 of each section 222 correspond to the cutting segments with PCD sections shown in connection with the preceding figures. The middle cutting segment 230.2 is in each case a steel-based segment without a PCD section, with which the removal of the PCD-based cutting segments 230.1, 230.3 can be adapted to the removal of the sector-like sections 222. Otherwise The structure of the tool 201 corresponds to that of the tool 101, which has been described in connection with FIG.

For cutting natural or artificial stone (in particular concrete, asphalt), a tool according to the invention with a corresponding diameter is clamped in a suitable device (flex, table saw, wall saw) and used in a manner known per se. The tool achieves a high work efficiency, and the wear of the tool is low, so that the tool has a long service life. The tool can basically be used in both dry and wet operation.

The illustrated tools can be modified in many ways. Thus, the number of sector-like sections and the cutting segments per section can be selected within wide ranges. It is also possible to construct a tool with a continuous edge region, ie without sector-like sections. The dimension of the toothing can be adapted to the requirements of the machining process, in certain cases can be dispensed entirely with the teeth.

In addition to the illustrated and already mentioned differences between different tools according to the invention, the individual cutting segments may be designed differently, for. B. with a different radius, a different height or another segment angle. The cutting segments can be attached at a different angle to the tangents of the carrier plate. According to all these parameters, the dimensions of the recesses in the edge region of the support plate are adapted. It is also possible to arrange on a single support plate different cutting segments or cutting segments with different orientation.

Further possible adjustments relate to the structure of the individual cutting segments, d. H. the materials used and layer thicknesses.

The illustrated embodiments relate to a tool in the form of a substantially circular disc. However, as stated above, the invention can also be realized within the scope of a drill bit. The cutting segments are secured along the circular, peripheral edge at the free end of the drill bit, the working edges of the cutting segments facing in the direction of rotation. As for the training of As regards the cutting edge as well as the arrangement and structure of the cutting segments, the statements made in connection with the cutting disks or the wall saw blade can also be applied to the case of a drill bit. The dimensions and materials used for the tool can - in a conventional manner - be adapted to the particular application, in particular to the stone material to be machined and the core diameter.

In summary, it should be noted that the invention provides a tool for cutting natural and artificial stone, which has a long service life and enables high cutting performance with good cutting quality.

Claims (15)

Tool (1; 101; 201) for cutting natural and artificial stone, comprising a support (10) to be rotated for a machining operation, wherein on the support (10) a cutting edge (20) is formed, which is a plurality of Carrier (10) arranged cutting segments (30), which consist of a sintered cemented carbide support material (31) and a layer (32) of polycrystalline diamond, characterized in that the cutting segments (30) have substantially the shape of a cylinder segment and that the cutting segments (30) are arranged on the carrier (10) so that a working edge (35) located at the front in the direction of rotation is formed by two edges (34a, 34b) bordering on a segment angle and defining the layer (32) of polycrystalline diamond ) of the cutting segment (30). Tool according to claim 1, characterized in that the segment angle 25 - 90 °, preferably 40 - 50 °. Tool according to claim 1 or 2, characterized in that the straight, meeting in the segment angle edges (34a, 34b) of the cutting segments (30) span a plane which is inclined against the direction of rotation and an angle of 45 - 97 °, preferably 70 - 90 °, in particular about 75 - 85 °, with a tangential to the cutting edge (20) includes. Tool according to one of claims 1 to 3, characterized in that the cutting segments (30) in cutouts (24) of an edge region (21) of the carrier (10) are arranged, wherein the two meeting, the working edge forming edges (34a, 34b ) of the cutting segments (30) at least partially project beyond an edge of the carrier (10). Tool according to claim 4, characterized in that each of the cutting segments (30) both with a front in the direction of rotation, substantially triangular End face (33) and with an opposite, substantially triangular end face (36) at least partially a wall (24b, 24c) of the respective cutout (24) contacted. Tool according to claim 4 or 5, characterized in that the cutting segments (30) in the respective cutout (24) of the carrier (10) attached over a large area, in particular soldered, are. Tool according to one of claims 4 to 6, characterized in that the edge region (21) of the carrier (10) is formed of tool steel and outwardly tapered. Tool according to claim 7, characterized in that the edge region (21) comprises a plurality of spaced-apart sector-like sections (22), wherein the cutouts (24) for receiving the cutting segments (30) in the sector-like sections (22) are arranged. Tool according to one of claims 1 to 8, characterized in that the working edge (35) is chamfered. Tool according to one of claims 1 to 9, characterized in that a ratio between an axial extent (H) of the cutting segments (30) and a radius (r) of the cutting segments (30) is at least 0.8, preferably at least 1.0. Tool according to one of claims 1 to 10, characterized in that a measured in the axial direction thickness (h) of the layer (32) of polycrystalline diamond at least 0.8 mm, preferably at least 1.2 mm. Tool according to one of claims 1 to 11, characterized in that the cutting segment (30) is mounted on the carrier (10) such that the straight edges (34a, 34b), which form the working edge (35) are arranged symmetrically to the cutting edge (20). Tool according to one of claims 1 to 12, characterized in that the carrier (10) is a substantially circular disc, and that the cutting edge (21) is formed on the periphery of the disc. Tool according to one of claims 1 to 13, characterized in that the carrier is designed as a substantially circular cylindrical drill bit, wherein the cutting edge is formed at a free end of the drill bit. Hand tool for cutting natural and artificial stone, comprising a tool (1; 101; 201) according to one of Claims 1 to 14.

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