EP0605850B1 - Blade body of fibre reinforced plastic for circular saw blades or abrasive cutting wheels - Google Patents

Abstract

The present invention relates to a blade body for circular sawblades and/or abrasive cutting wheels, comprising a circular disc body (2) consisting at least partially of a plastics material (6) reinforced with embedded fibres (4). The fibres (4) are arranged in a plurality of fibre layers (16, 18) which lie one above the other, are bonded cohesively or adhesively, are planar, shaped as circular discs and concentric to the disc body (2). In a first type of fibre layer (16), the fibres (4) are aligned rectilinearly in an at least approximately radial direction - with respect to the disc body (2) - and are arranged in a uniform distribution over the circumference. In a second type of fibre layer (18), the fibres (4) have an at least approximately circular path which is substantially concentric to the disc body (2), the two types of fibre layers (16, 18) being arranged in the disc body (2) with a distribution chosen in dependence on the size of the disc body (2). <IMAGE>

Description

The present invention relates to a master sheet for Circular saw blades and / or cut-off wheels according to the Preamble of claim 1, see US-A 3 315 418.

For circular saw blades intended for stone processing or cut-off wheels, whereby on the outer circumference of the master blade peripheral, mostly diamond-tipped cutting elements (Cutting segments) are attached for certain applications very large stem leaves with a leaf diameter of up to 5.00 m is required. So now with such large leaf diameters the weight of the base leaf attempts have not been made to be too high, the disc body instead of metal from a plastic material to manufacture.

US-A-3 315 418 describes a plastic grinding wheel, which is a fiber reinforcement made essentially circular extending fibers and radial fibers. Several fiber layers are provided, each Location from a combination of essentially circular Fibers and radial fibers. They are also individual fibers are also relatively far apart, i.e. it is a relatively small number of fibers or low fiber density.

From DE-U-88 11 470 (or the corresponding one Publications DE-A-38 30 819 and EP-A-0 356 923) a saw blade made of a fiber-reinforced plastic known, but fiber in the form of fabric-like Mats are embedded, specifically in the Form of circular sector-shaped fiber mats that are rotationally symmetrical are arranged and at their radial Edge sections overlap each other.

A circumferential grinding wheel is known from DE-C-27 40 891, which consists of an inner hub part and an outer, a grinding ring made of rim parts carrying grinding wheels exists, with hub and rim over preloaded - and thus performing the function of "spokes" - wires, fibers or Threads are interconnected. Here are the "spokes" embedded in plastic. In addition to the "spokes" is said to be a common one in the plastic, of fabric mats formed fiber reinforcement can be embedded.

DE-A-2 045 814 describes a synthetic resin saw blade, which radially running, with 7.5 cm relatively wide bands contains boron epoxy. Each volume in turn contains in the longitudinal direction of the belt and therefore parallel to each other Boron threads. The individual ribbons run together crossing radially through the center of the leaf. The Boron threads are primarily used for production the cutting action by placing it on the outer circumference of the sheet end and act as a "cutting or grinding surface".

It has now been shown in practice that the previously known Plastic master sheets very unstable or unstable and are in operation with the application of forces due to running and by heating due to material stress get over. This leads to poor running properties and also to poor machining quality during the use of saw blades or cutting discs. In unfavorable cases, the twists that occur even to destroy the blade and / or damage of the respective workpiece. These problems could have not yet been satisfactorily resolved, so that plastic master sheets are not yet available for all applications could enforce.

The present invention is therefore based on the object eliminate the problems outlined and starting out from the mentioned prior art to a master sheet create which under practically all operating conditions ensures optimal running properties and machining results, and which also has a long lifespan owns.

According to the invention this is achieved in that the two types of fiber flow in different fiber layers on the one hand only with the radial course and on the other hand are only arranged with the circular course, where a plurality of the fiber layers with one in Depending on the size of the disc body chosen Distribution of the two different types of layers one above the other and integrally connected in the disc body is arranged, the fibers such are arranged close to each other in the area of the fiber layers a fiber density with a volume fraction of about 60 to 70 vol .-% is present.

Here, the respective radially aligned fibers effect high stability of the master blade in the radial direction, and the substantially circular fibers stabilize the blade in the circumferential direction, i.e. against bending around the radial direction, being a particular advantage It should be emphasized that the mechanical properties practical about the scope of the master sheet according to the invention are absolutely constant, because in contrast to the state the technology is based on the fiber orientation according to the invention and distribution practically an "isotropy" within of the master sheet reached.

It is particularly advantageous if each fiber layer is one has a central opening, so that it is thus an annular disc is formed, the individual fiber layers of the master sheet with regard to their inside / outside diameter ratio especially different sizes are. The distribution of these changes in their diameter ratios distinctive fiber layers within the Master sheet also takes place according to the invention in Adaptation to the dimensions (diameter, thickness) of the Master blade in such a way that an optimal "stability distribution" within the master sheet according to the invention can be reached.

According to the invention, the fibers are thus as accurate as possible aligned in the respective orientation are included but essentially free of tension in the plastic material of the master sheet embedded. The radial fibers end at both ends "blind", i.e. they are - apart from to a material bond existing over its entire length the plastic material - not particularly supported at the end, i.e. not "tied up". The essentially circular Aligned fibers can be found in the corresponding Layers are advantageously laid as a continuous material in spiral form be so that the alignment is very slightly different from the ideal Circular shape differs, but this does not cause any disadvantage.

According to the invention, the fibers are like this in every fiber layer arranged closely next to each other that a high fiber density is achieved. The volume fraction of the The fiber material is about 60-70% by volume.

In principle, any fiber material could be used are, for example, glass fibers. But it did proven to be particularly advantageous, a carbon fiber material use, compared to high-strength (HT) carbon fibers the so-called "highly rigid" (HM = high modulus) Carbon fibers are best suited because this is a special one favorable modulus of elasticity can be achieved. The elastic properties of the master sheet according to the invention are even better than those of a master sheet from steel.

The master sheet according to the invention is characterized by optimal Running properties under almost all operating conditions, due to its low weight and long Service life (durability).

Further advantageous design features of the invention are in the subclaims and the following description contain.

Fig. 1

eine Draufsicht eines erfindungsgemäßen Stammblattes,

Fig. 2

einen gegenüber Fig. 1 vergrößerten, stark schematischen Querschnitt durch das erfindungsgemäße Stammblatt in der kreisbogenförmig und konzentrisch verlaufenden Schnittebene II-II gem. Fig.1,

Fig. 3

einen ebenfalls stark schematischen Radialschnitt längs der Linie III-III in Fig. 1,

Fig. 4A bis 4D

Beispiele für unterschiedliche Faser-Lagen mit radialer Orientierung der Fasern,

Fig. 5

ein Beispiel einer Faser-Lage mit im wesentlichen kreisförmig verlaufenden Fasern,

Fig. 6

eine gegenüber Fig. 1 vergrößerte, detailliertere Darstellung eines in Fig. 1 mit VI bezeichneten Bereichs des äußeren Umfangs des erfindungsgemäßen Stammblattes,

Fig. 7

eine vergrößerte Darstellung des Bereichs VII in Fig. 6,

Fig. 8

eine Ansicht auf den Außenumfang des Stammblattes in Richtung der Blattebene in Pfeilrichtung VIII gemäß Fig. 7,

Fig. 9

einen Radialschnitt längs der Linie IX-IX in Fig. 7 und

Fig. 10

einen Radialschnitt längs der Linie X-X in Fig. 7.

The invention will be explained in more detail by way of example below with reference to the drawing. Show:

Fig. 1

a plan view of a master sheet according to the invention,

Fig. 2

an enlarged compared to Fig. 1, highly schematic cross section through the master sheet according to the invention in the circular arc and concentric section plane II-II acc. Fig.1,

Fig. 3

a likewise highly schematic radial section along the line III-III in Fig. 1,

4A to 4D

Examples of different fiber layers with radial orientation of the fibers,

Fig. 5

an example of a fiber layer with essentially circular fibers,

Fig. 6

2 shows an enlarged, more detailed illustration of an area of the outer circumference of the master sheet according to the invention designated by VI in FIG. 1,

Fig. 7

6 shows an enlarged view of area VII in FIG. 6,

Fig. 8

7 shows a view of the outer circumference of the base sheet in the direction of the sheet plane in the direction of arrow VIII according to FIG. 7,

Fig. 9

a radial section along the line IX-IX in Fig. 7 and

Fig. 10

a radial section along the line XX in Fig. 7th

The same in the different figures of the drawing Parts always have the same reference numerals and are therefore usually only described once. Thus, every one that occurs only once applies A description of one part analogous to the other Drawing figures in which this part with the corresponding Reference numerals can also be seen.

1, a master sheet 1 according to the invention is simplified, i.e. without extensive cutting elements. The master sheet 1 consists of a circular disc body 2, which in turn at least partially, but in doing so mainly, from a reinforced with embedded fibers 4 Plastic material 6 consists; see Fig. 2 and 3. The disk body 2 preferably has a central one Assembly opening 8. On the outer circumference 10 of the window body 2 are about a - in the following based on the 6 to 10 to be explained in more detail - mounting device 12 cutting elements 14 attachable.

As can now be seen from FIGS. 2 and 3, the fibers 4 are according to the invention in a variety of superimposed, Cohesively connected, flat, circular disc-shaped and to the disk body 2 concentric fiber layers 16, 18 arranged. There are basically two different ones Types of fiber layers are provided, namely in one 4A to 4D exemplified - first type of fiber layer 16 the fibers 4 only in one - related on the disc body 2 - at least approximately radial Directed in a straight line and in one over the circumference even distribution and preferred here arranged as close together as possible. In a second Type of fiber layer 18 - see Fig. 5 - have the fibers 4 only an at least approximately circular one the disk body 2 substantially concentric Ver run, preferably as close as possible lie together and evenly distributed in the radial direction are (more uniform than perhaps in Fig. 5 the Appears). These two are now according to the invention Types of fiber layers 16, 18 to fit the dimensions (Diameter and thickness) of the disc body 2, i.e. in adjustment to the "stabilization distribution" required with these dimensions, each with a specific one for which Thickness required number and with a certain Distribution (order of stacking; "combination" of the two layer types 16, 18) in the disc body 2 arranged. 2 and 3 are for reasons of clarity only a few fiber layers 16, 18 indicated; in In reality, the disc body 2 is made up of a great deal more (a plurality of) layers 16, 18 together, preferably the layers 16 with the radially aligned fibers 4 outweigh quantitatively.

4A to 4D and 5, each fiber layer 16, 18 has a central opening 20 and is thus designed in the form of an annular disk. It is now provided according to the invention, the individual Fiber layers 16, 18 with regard to their interior and / or Outside diameter, i.e. with regard to their diameter ratios (Inner diameter to outer diameter), from layer to train differently for location. This is in Figure 4A well recognizable up to 4D. The disc body 2 is made from these - yourself by the type of fiber orientation and / or by differentiating the diameter ratios - fiber layers 16, 18 formed, these layers in a certain, for the respective dimensions of the disk body 2 distribution of each other optimized for stabilization layered and uniform with synthetic resin material connected (embedded).

It is special for the production of the disc body 2 advantageous if the individual fiber layers 16, 18 each are prefabricated as foils 22 (FIGS. 4A to D and 5), which is why the fibers 4 are initially on a carrier layer (in the Drawing not recognizable) aligned and pre-fixed as well subsequently glued with a synthetic resin. After individual foils 22 are formed when the synthetic resin hardens, in the further manufacture of the disc body 2 allow it to be handled well for stacking.

In this context it should be noted that the individual Fiber layers 16, 18 also on the finished disc body 2, i.e. on a section through this disc body 2, easy to recognize are, especially between the layers one of the carrier layers is arranged. Here it can are preferably carrier networks, since these are the material cohesion Favor connection between the layers, because easily penetrated by the plastic material can be.

In one illustrated in Figs. 2 and 3, particularly advantageous embodiment of the master sheet according to the invention 1, the disc body 2 consists of three parallel Layers, namely from two outer, from the fiber layers 16, 18 formed outer layers 24 and 26 and one middle layer 28 arranged between them. The middle layer 28 could also - roughly analogously to the outer layers 24, 26 - be formed from fiber layers, however there is the middle layer 28 in the preferred embodiment the invention from individual, in particular fiber-reinforced Plastic prefabricated fillers and / or made of another filling material, especially with nonwoven reinforced plastic. This non-woven fabric is made then preferably made of HF carbon fibers. In the case of the prefabricated Filling pieces are preferably with carbide carbon fibers reinforced, these fibers in particular run in the same direction within the filler pieces; it are so-called "unidirectional fabrics".

In the preferred three-layer structure of the disc body 2, the two outer layers 24, 26 are related the design and arrangement of the individual fiber layers 16, 18 - based on the center plane 30 of the disc body 2 - in particular mirror-symmetrical. This too Feature was tried to clarify in FIGS. 2 and 3.

As can further be seen from FIGS. 2 and 3, the disk body has 2 preferably on its two opposite Surfaces each have a wear protection coating 32, in particular each of a polyester fabric are formed. Through these superficial wear protection coatings 32 are the - basically somewhat sensitive to friction and abrasion - Fibers 4 from wear protected. For these coatings 32 is preferred used a material as it is under the trademark "Diolen" is known.

In a further embodiment of the invention, the Disk body 2 in the area of its center plane 30 channels 34 for a cooling medium, these channels 34 from the inner Surface area of the disc body 2 up to its outer circumference 10 run through the middle layer 28. In his inner surface area, the disc body has 2 inflow openings 36 (see Figs. 1 and 3), each in axial direction through the one outer layer 24 into the Extend middle layer 28 and there in each of the Skip channels 34. The channels 34 run in particular radial and open on the outer circumference 10 of the disk body 2 free to the outside. The master sheet 1 according to the invention with the central mounting opening 8 on a suitable, Not shown clamping flange mounted, this Clamping flange then also for the supply of a cooling medium serves, which in the inflow openings 36 and thus in the Channels 34 is initiated.

It is now a preferred embodiment based on FIGS. 6 to 10 the mounting device 12 already mentioned above for in particular detachable (exchangeable) mounting of the Cutting elements 14 are explained.

Preferably in the outer peripheral region of the disc body 2 one or more parts on each of its two sides Retaining ring 40 attached. These two retaining rings 40 lie in parallel planes, and the outer circumference of the Disk body 2 is in some areas between these retaining rings 40 arranged. In the preferred embodiment is each retaining ring 40 in such a ring recess Disc body 2 arranged sunk (see in particular 9 and 10) that the outer surfaces of the disc body 2 and the retaining rings 40 each in a continuous Level. The fastening of the retaining rings 40 on the disk body 2 is preferably carried out by riveting, 9 according to FIG. 9 rivets 42 aligned Bores of the retaining rings 40 and the disc body 2 extend. The rivets 42 are preferably countersunk rivets formed and consist in particular of copper. The retaining rings In contrast, 40 are preferably made of steel. The Retaining rings 40 protrude beyond the outer periphery 10 of the disk body 2 at least slightly in the radial direction to the outside. On the outer circumference of the retaining rings 40 are now in accordance with the invention Fixed segment holder elements 44, in one evenly distributed over the circumference and each spaced apart arrangement; see in particular 6 and 7. Preferably, the segment holder elements 44 welded to the retaining rings 40. Between each Segment holder elements 44 are thus peripheral recesses formed for receiving foot parts 46 of the cutting elements 14 serve, and are each in the circumferential direction between the segment holder elements 44 according to the invention Cutting elements 14 each have a positive connection Clamp connection attachable. Each exists for this Cutting element 14 from a foot 46 and a fastened to it, especially soldered and preferably diamond-tipped Cutting surface 48. The segment holder elements 44 and the feet 46 of the cutting elements 14 are according to the invention each via in particular prism-shaped guide surfaces 50, 52 engaged. In the illustrated, preferred The exemplary embodiment are the guide surfaces 50 of FIG Segment holder elements 44 each as a prism groove with essentially triangular (V-shaped) groove cross section, while the guide surfaces 52 on the feet 46 the cutting elements 14 as corresponding prism approaches a matching triangular cross-section are. However, this can also easily be done the other way round be. It is now provided according to the invention that the guide surfaces 50 of each segment holder element 44 in the radial direction at an acute angle α - im the example shown is about 3 ° - to the corresponding one Radius run obliquely that each for the foot 46 of the cutting element 14 provided recess in their clear, measured in the circumferential direction in radial At least slightly narrowed from inside to outside, that means the outer width X is always smaller than the inner width Y (see FIG. 7). The foot is 46 each cutting element 14 in its radially inner, the Retaining rings 40 facing area in the circumferential direction designed to expand that after insertion in radial direction from the outside inwards into the recess the guide surfaces between each two segment holder elements 44 52 of the foot 46 to the flush system to the Guide surfaces 50 of the segment holder elements 44 brought can be. Because of the angular position described the guide surfaces 50, 52 is thus a positive fit causes secure holding of the cutting elements 14. To the To ensure spreadability of the feet 46 have these each have a radial slot 54, which is in radial Extends from the inside to the outside in the foot 46. Each slot has a preferably circular extension, into which an expansion element, in particular an adapter sleeve 56, can be inserted perpendicular to the disc plane. This causes the feet 46 to spread apart; see the Double arrow 58 in Fig. 8. According to the invention is therefore a Detachable or exchangeable holder of the cutting elements 14 provided, thus in the direction of that shown in FIG. 7 Double arrow 60 can be assembled or disassembled can.

As can be seen in particular from FIGS. 9 and 10, tower above the retaining rings 40 the outer circumference 10 of the disk body 2 radially outwards. Furthermore, the inner surface areas the segment holder elements 44 and the feet 46 of the Cutting elements 14 each in the radial direction from the outer circumference 10 of the disc body 2 spaced. This will according to the invention between the retaining rings 40 on the one hand and between the outer periphery 10 of the disc body 2 and the segment holder and cutting elements on the other hand in Circumferential direction channel 62 is formed. In these circumferential channel 62 on the one hand already open the above explained channels 34 of the disc body 2, and on the other hand lead from this extensive channel 62 Through openings 64 of the segment holder elements 44 whose outer peripheral surfaces 66. That on the channels 34 of the Disc body 2 supplied cooling medium can thus on Outer circumference, i.e. in the area of the segment holder elements 44, emerge.

9 and 10 can finally be seen that each segment holder element 44 and preferably also each Cutting element 14 or its base 46 with a base 68 engages approximately positively between the two retaining rings 40 and at the same time adjoining the base 68 Shoulders rests on the outer circumference of the retaining rings 50.

Finally, the manufacturing process should now briefly of the master sheet 1 according to the invention will be explained.

First, the fiber layers 16, 18 and the foils 22 with the desired fiber orientation and with certain Prefabricated inside / outside diameter ratios. For this purpose, the fibers 4 are preferably thread-like Endless material in particular laid on a backing layer. In the case of the fiber layer 16, the fibers 4 are used for alignment expediently in the radial direction by one Variety of fixing elements that they wound in the area of the fiber layer 16 to be formed in each case in a straight line in a radial direction Direction across a level. In the case of fiber layers 18, the fiber material is preferably used of a laying circle laid spirally, but almost circular due to a tight installation Course can be achieved. The fibers laid in this way 4 are with a plastic binder, especially one Resin, glued by brushing with this resin will. After this plastic hardens a continuous sheet 22, which in the the desired size is "cut out"; in case of radial fibers 4 become these in the inner and outer peripheral area the annular disk-shaped film 22 separated. The fibers 4 are therefore essentially tension-free, but exactly aligned in the respective orientation the film 22 or in the respective fiber layer 16, 18. Die Carrier layer, in particular a relatively coarse-mesh carrier network, preferably remains part of the film 22. Das Carrier network is preferably originally on a particular carrier made of paper arranged; this carrier material is then preferably from Foil 22 removed, so that then only the carrier network component the film 22 remains.

With the prefabricated fiber films 22 then Disc body 2 formed in which a variety of particular different foils 22 are stacked on top of one another and the same material with plastic, especially with the the same resin that is used to form the foils 22 was connected. The distribution of the slides 22 takes place according to the invention in adaptation to the dimensions of the disc body to be manufactured such that a for the respective dimensions optimal stabilization distribution in Disk body 2 is reached. In the preferred three-layer Structure of the disc body 2 is first one the outer layers 24, 26 by corresponding layers Fiber layers 16, 18 are formed. Then will the middle layer 28 is formed by e.g. appropriate Filling elements or filling materials are placed. Here channels 34 are also preferably produced, for which purpose corresponding cavities can be left blank, or it becomes something that can later be removed, for example by melting Material inserted. It will then finally be the other outer layer applied, for which purpose fiber layers 16, 18 mirror-symmetrical to the first outer layer, i.e. in reverse Order to be relocated.

During this laying of the fiber layers 16, 18 can also immediately the recesses for the retaining rings 40 of the mounting device 12 are formed (molded). Alternatively but you can also add these retaining ring recesses later formed by mechanical processing will.

All individual layers and layers are made of the same material bonded with synthetic resin. The finished installed window body 2 is then preferably used during curing pressed and annealed.

Finally, the mounting device 12 for the Cutting elements 14 mounted, which probably no further explanations may be needed more.

Claims (16)

1. Base blade (1) for circular saw blades and/or abrasive cutting discs, comprising a circular disc body (2) consisting at least partially of a plastics material (6) reinforced with embedded fibres (4), the fibres (4) being arranged in a plurality of plane, circular-disc-shaped fibre layers (16,18) concentric with the disc body (2) and - relative to the disc body (2) - being oriented in a uniform distribution over the circumference at least approximately radially and rectilinearly in a first kind of orientation and running at least approximately circularly and substantially concentrically in a second kind of orientation, characterised in that the two kinds of fibre orientation are arranged in different fibre layers (16,18), on the one hand only with the radial orientation and on the other hand only with the circular orientation, a multiplicity of the fibre layers (16,18) being arranged in the disc body (2), lying one above the other and adhesively bonded, with a distribution of the two different kinds of layers selected in dependence on the size of the disc body (2), the fibres (4) being arranged so close together that a fibre density with a proportion by volume of about 60 to 70% by volume exists in the region of the fibre layers (16,18).
2. Base blade according to Claim 1, characterised in that the fibre layers (16, 18) are each constructed in the shape of an annular disc with specific inside/outside diameter ratios which differ in each case particularly from layer to layer, the fibre layers (16,18) differing by their diameter ratios being arranged in the disc body (2) in a layer distribution determined in dependence on the size of the disc body (2).
3. Base blade according to Claim 1 or 2, characterised in that the fibres (4) in each fibre layer (16,18) are arranged close together and in a uniform distribution in the layer plane.
4. Base blade according to one or more of Claims 1 to 3, characterised in that each fibre layer (16,18) is formed of a prefabricated sheet (22), the fibres (4) being arranged in this sheet (22) in a manner embedded in plastics material (6), and a multiplicity of these sheets (22) being adhesively bonded to one another in a manner lying one on top of the other in a specific combination.
5. Base blade according to one or more of Claims 1 to 4, characterised in that the fibres (4) in each fibre layer (16, 18) are arranged in a manner lying on a supporting layer, particularly a supporting network.
6. Base blade according to one or more of Claims 1 to 5, characterised in that the disc body (2) comprises three parallel layers (24, 26, 28), namely two exterior outer layers (24, 26), each formed from the fibre layers (16, 18), and a middle layer (28) lying therebetween.
7. Base blade according to Claim 7, characterised in that the middle layer (28) comprises individual filling pieces, particularly filling pieces prefabricated from fibre-reinforced plastic, and/or other filling material, particularly plastic reinforced with fibre web.
8. Base blade according to Claim 6 or 7, characterised in that the two outer layers (24, 26) are constructed, with respect to the configuration and arrangement of the individual fibre layers (16, 18), with mirror symmetry relative to the median plane (30) of the disc body (2).
9. Base blade according to one or more of Claims 1 to 8, characterised in that the disc body (2) has channels (34) for a cooling medium in the region of its median plane (30), the channels (34) running from the inner region of the disc body (2) as far as the outer circumference (10) and particularly through the middle layer (28).
10. Base blade according to one or more of Claims 1 to 9, characterised in that the disc body (2) has a wear-protection coating (32) preferably formed of polyester fibre fabric on each of its two surfaces.
11. Base blade according to one or more of Claims 1 to 10, characterised in that the disc body (2) has a holding means (12) in its outer circumferential region for the holding, particularly releasable holding, of preferably diamond-impregnated cutting elements (14).
12. Base blade according to Claim 11, characterised in that each cutting element (14) is seated in a peripheral recess in the base blade by a root part (46) in such a manner that a form fit exists both in the radial direction of the disc body (2) and transversely to the disc plane.
13. Base blade according to Claim 12, characterised in that one of two single- or multi-part holding rings (40) is fastened, in particular riveted, on each of the sides of the disc body (2) in the outer circumferential region of the latter, segment-holder elements (44) being fastened, preferably welded, to the outer circumference of these holding rings (40) and uniformly distributed over the circumference in each case spaced apart from one another, and the recesses, which receive the root parts (46) of the cutting elements (14) and in which the cutting elements (14) can be fastened in each case by a clamping connection which brings about the form fit, being formed in each case between the segment-holder elements (44).
14. Base blade according to Claim 13, characterised in that the segment-holder elements (44) and the cutting elements (14) are in engagement in each case by way of guiding surfaces (50, 52), particularly prism-shaped guiding surfaces, each recess provided for the root part (46) of the cutting element (14) narrowing, in its clear width measured in the circumferential direction of the disc body (2), from the inside outwards in the radial direction, and each cutting element (14) being able to be spread apart in the circumferential direction in the inner region, facing the holding rings (40), of its root (46).
15. Base blade according to Claim 13 or 14, characterised in that the holding rings (40) project radially outwards beyond the outer circumference (10) of the disc body (2) in such a manner that a channel (62) running in the circumferential direction is formed in this region between the holding rings (40) on the one hand and between the outer circumference (10) of the disc body (2) and the segment-holder and cutting elements (44, 14) on the other hand, into which channel on the one hand the channels (34) of the disc body (2) open, and from which channel on the other hand through openings (64) of the segment-holder elements (44) lead to the outer circumferential surfaces (66) of the latter.
16. Base blade according to one or more of Claims 13 to 15, characterised in that each segment-holder element (44) and/or each cutting element (14) engages with a form fit between the two holding rings (40) by a root projection (68).

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