EP4217139A1

EP4217139A1 - Sawblade and hole saw

Info

Publication number: EP4217139A1
Application number: EP21773713.9A
Authority: EP
Inventors: Donghui DING; Daniel Grolimund
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-09-22
Filing date: 2021-09-06
Publication date: 2023-08-02
Also published as: WO2022063552A1; CN116323060A; US20230398617A1; DE102020211809A1

Abstract

The invention relates to a sawblade (100) with a plurality of wave-shaped teeth (Z₁,Z₂) which are formed on a continuous base section (102) of the sawblade (100). Each of the teeth (Z₁,Z₂) has a paired tooth base (140, 142) with a tooth base upper face (150, 152) and a hard metal blade (114, 116) arranged thereon. Each tooth base (140, 142) adjoins the hard metal blade (114, 116) arranged thereon in a flush manner on both sides along a longitudinal axis (120) of the base section (102), and each hard metal blade (114, 116) and each tooth base upper face (150, 152) has two bevels and/or convexly rounded areas extending substantially along the longitudinal axis (120) of the base section (102), wherein the teeth (Z₁,Z₂) are designed to be set and/or unset.

Description

description

title

saw blade and hole saw

State of the art

The present invention relates to a saw blade having a plurality of wave-like shaped teeth formed on a continuous base portion of the saw blade, the teeth each having an associated tooth base with a tooth base top and a hard metal cutting edge arranged thereon. In addition, the subject of the invention is a hole saw.

A saw blade having a plurality of wave-like shaped teeth formed on a continuous base portion of the saw blade is known in the prior art, the teeth each having a hard metal cutting edge. For example, EP 0 054 885 A2 describes a saw blade in the form of a band saw blade equipped with hard metal plates. This band saw blade should be characterized by a long service life and a high permissible stepping speed and be suitable for cutting very hard materials such as metals or stones. For this purpose, the band saw blade is unset and the hard metal plates are fastened to seating surfaces that are perpendicular to the longitudinal extent of the saw blade or are only slightly inclined forward. The hard metal plates have a height between 1/3 to 4/5 of a respective tooth height and protrude on both sides with undercut free-cut widenings over the saw blade thickness.

Disclosure of Invention

The invention relates to a saw blade with a multiplicity of wave-shaped teeth which are formed on a continuous base section of the saw blade, the teeth each having an associated tooth base with a tooth base upper side and a hard metal cutting edge arranged thereon. Every Each tooth base is flush with the hard metal cutting edge on both sides along a longitudinal axis of the base section, and each hard metal cutting edge and each top side of the tooth base has two chamfers and/or convex curves that extend essentially along the longitudinal axis of the base section, with the teeth being unset and/or set .

This results in comparatively smooth saw cuts combined with increased cutting efficiency. In addition, a higher sawing speed is possible with an improved service life of the saw blade. The carbide cutting edges are flush with the respective tooth base of the tooth on both sides and are therefore stable and particularly robustly supported. Due to the complete support of the hard metal cutting edges, the hard metal cutting edges fastened to the teeth have a particularly long service life. The base of the tooth in turn is preferably flush with the base section of the saw blade. A tooth base upper side formed by the respective tooth base and the hard metal cutting edge embedded therein flush on the upper side has a planar design and falls off in a straight line, starting from a tooth tip to the tooth back. In the context of the present description, the term "set" defines the preferably opposite bending out of teeth that follow one another directly from a central plane defined by the rectangular base section of the saw blade. Regardless of the presence of a set, all teeth of the saw blade preferably have the same height. The geometry of the teeth of the saw blade according to the invention preferably approximates the so-called K-shape when viewed from the side (cf. inter alia Brockhaus, "Naturwissenschaften und Technik"; volume 4; page 224; 1989).

The chamfers of each hard metal cutting edge preferably have essentially the same width.

This results, among other things, in reduced cutting forces and self-centering of the saw blade in the saw or kerf in the material to be processed. The chamfers increase tear resistance and impact resistance. In the context of the present description, the term “chamfer” is understood to mean a planar or prismatic chamfering or beveling of a workpiece edge. In one embodiment, the lands of each tooth have a different width.

As a result, even more effective self-centering within the saw or kerf is guaranteed.

The convex curves preferably have a radius that is essentially the same size.

As a result, mechanical stresses in the area of the cut surfaces can be further reduced.

According to a technically favorable further development, two teeth directly following one another along the longitudinal axis are set opposite to one another.

The cutting forces occurring during the sawing process can be further reduced due to the free cut of the saw blade that is realized in this way.

Preferably, at least one tooth is unset and the two teeth directly following it along the longitudinal axis are oppositely set and this set sequence is repeated along the longitudinal axis across all teeth of the saw blade.

This periodic set sequence results in a wider saw or kerf.

In the case of a further development, it is provided that at least one tooth is unset and two further teeth immediately following it along the longitudinal axis are set opposite to one another at a first setting angle and two further teeth directly following the teeth set oppositely in the first setting angle along the longitudinal axis in one second set angle are set opposite to each other and this set sequence is repeated along the longitudinal axis over all teeth of the saw blade. As a result, any tendency of the saw blade to jam in the workpiece can be further reduced. The width of the bevels, their bevel angles and/or the radii of the convex curves can vary individually depending on the setting angles.

The first angle of twist is preferably smaller than the second angle of twist.

This increases the angles of the sets in the cutting direction.

The hard metal cutting edges preferably form a tooth tip above a concave chip space of each tooth pointing in the cutting direction.

As a result, there is a high cutting or sawing capacity. A tooth back is essentially straight.

The hard metal cutting edges are preferably firmly connected to the tooth base of the teeth, in particular thermally joined to them.

This results in a particularly robust connection, which is easy to produce in terms of production technology, between the hard metal cutting edges and the tooth base of the teeth that carries them.

The base section of the saw blade is preferably formed from a tempered steel and the hard metal cutting edges are preferably formed from a tungsten carbide-cobalt hard metal.

This ensures sufficient flexibility of the saw blade. Furthermore, an excellent cutting performance combined with a long service life of the saw blade can be achieved.

In addition, the invention relates to a hole saw. This hole saw is formed with a saw blade that is essentially bent into a ring and is preferably designed as described above.

As a result, a hole saw or drill bit with a considerably improved cutting performance in relation to previously known solutions can be realised. Brief description of the drawings

The invention is explained in more detail in the following description on the basis of exemplary embodiments illustrated in the drawings. Show it:

1 shows a schematic partial side view of a first embodiment of a saw blade according to the invention,

FIG. 2 shows a schematic partial plan view of the saw blade from FIG. 1 ,

3 is a schematic front view of two teeth of the saw blade of FIG

figure 2,

4 shows a schematic partial top view of a second embodiment of a saw blade, which is unrestricted in comparison to the first embodiment with an otherwise identical design,

5 shows a schematic front view of two teeth of a third embodiment of a saw blade,

6 shows a schematic front view of two teeth of a fourth embodiment of a saw blade,

7 shows a schematic partial plan view of a fifth embodiment of a saw blade,

Fig. 8 is a schematic front view of three teeth of the saw blade of Fig. 7,

9 shows a schematic partial plan view of a sixth embodiment of a saw blade,

Fig. 10 is a schematic front view of the five teeth of the saw blade of Fig. 9;

11 is a detailed partial front view of a tooth of the first embodiment of the saw blade. 12 is a detailed partial front view of a tooth of the third embodiment of saw blade, and

Fig. 13 is a detailed partial front view of a tooth of the fourth embodiment of saw blade.

Description of the exemplary embodiments

In the figures, structurally essentially identical elements with the same or comparable function are provided with the same reference symbols throughout for reasons of economy of drawing and are described in more detail only once.

1 shows a first embodiment of a saw blade 100, which preferably has a large number of similar, wave-shaped teeth, of which only two teeth Zi,2 are designated here as a representative of all the other teeth of the saw blade 100. The teeth Zi,2 are preferably formed integrally on a continuous band-shaped or rectangular profile-like base section 102 of the saw blade 100 .

The saw blade 100 with the base section 102 illustratively has a center plane M in which a longitudinal axis 120 runs. A preferred cutting direction 198 of the saw blade 100 is indicated by an arrow 198 .

Each of the teeth Zi,2 preferably has an associated, solid tooth base 140, 142 or a tooth shank with a tooth base top 150, 152 and a hard metal cutting edge 114, 116 arranged thereon. The hard metal cutting edges 114, 116 illustratively each form a tooth tip 158, 160 above a chip space 154, 156 of each tooth Zi,2 pointing in the cutting direction 198. The tooth base tops 150, 152 and tops 170, 172 of the hard metal cutting edges 114, 116 embedded in the respective tooth base 140, 142 adjoin one another flush and each essentially form one—apart from the continuous bevels (see especially FIG. 3). flat tooth top 180, 182, which, starting from the raised tooth tips 158, 160 to a respective tooth back 162, 164 of the teeth Zi, 2, preferably slopes slightly in a straight line, ie does not run parallel to the longitudinal axis 120. The tooth backs 162, 164 the teeth Zi,2 are only approximately straight as an example here. The teeth Zi,2 and the teeth of the saw blade 100 (not shown) also preferably have the same height H in each case.

The hard metal cutting edges 114, 116 are preferably firmly connected to the respective tooth base 140, 142 of the respectively assigned tooth Zi,2, in particular thermally firmly joined to it. The thermal joining between the tooth bases 140, 142 of the teeth Zi,2 and the hard metal cutting edges 114, 116 can take place, for example, by brazing or welding. The base section 102 of the saw blade 100 is preferably formed with a (highly) tempered steel and the hard metal cutting edges 114, 116 can be implemented, for example, with a tungsten carbide-cobalt hard metal.

Fig. 2 shows the base section 102 of the saw blade 100 of Fig. 1, on which the teeth Zi,2 are formed, with the hard metal cutting edge 114 being fastened in the area of the tooth base upper side 150 of the tooth Zi and the hard metal cutting edge 116 being fastened in the area of the tooth base upper side 152 of the tooth Z2 is. The teeth Zi,2 are set here only by way of example, i.e. bent in opposite directions to one another out of the central plane M of the base section 102 of the saw blade 100. Alternatively, the teeth Zi,2 of the saw blade 100 can also be designed without set (see especially FIG. 4). The saw blade 100 is guided in the cutting direction 198 through the workpiece to be machined, which is not shown here.

FIG. 3 shows the base section 102 of the saw blade 100 of FIG. 2, on which the set teeth Zi,2 are formed. The teeth Zi,2 of the saw blade 100 are illustratively located in a saw channel S or a kerf of a workpiece W to be machined. The longitudinal axis 120 of the base section 102 runs within the center plane M of the base section 102 and the cutting direction 198 of the saw blade 100 through the workpiece W points out of the plane of the drawing in the representation of FIG.

Preferably, each tooth base 140, 142 of each tooth Z1, 2 along the longitudinal axis 120 of the base section 102 is flush on both sides with the hard metal cutting edge 114, 116 arranged thereon. In addition, each hard metal cutting edge 114, 116 and each tooth base upper side 150, 152 of the teeth Zi, 2 each have two essentially along the longitudinal axis 120 of the base Section 102 extending, ie here running approximately perpendicularly to the plane of the drawing, continuous, flat chamfers Fi 4 or so-called bevels. The tooth tops 150, 152 of the teeth Zi,2 lie behind the hard metal cutting edges 114, 116 or their tops 170, 172 in relation to the plane of the drawing.

The teeth Zi,2 can be either set or unset, as shown in the drawing. In the first embodiment of the saw blade 100 shown here, the bevels Fi 4 preferably each have approximately the same width, only the widths BI, 2 of the bevels Fi, 4 lying on the outside in relation to the central plane M being indicated for the sake of clarity in the drawing .

FIG. 4 shows a second embodiment of a saw blade 200 with a base section 202 which extends along the center plane M of FIG. 1 with the longitudinal axis 120 . A plurality of teeth is preferably formed on the base section 202, of which only two teeth Z ₃ , 4 are shown and labeled as representative of all the others. A hard metal cutting edge 214 is in turn embedded, preferably flush with a tooth base upper side 206 of tooth Z3. Correspondingly, the tooth base upper side 208 of the tooth Z4 also has a hard metal cutting edge 216 . The top side of the tooth base 206 and the hard metal cutting edge 214 of the tooth Z3 preferably each have a continuous bevel FS,6 on both sides, with the bevels Fs,6 being oriented approximately along the longitudinal axis 120 . Correspondingly, the upper side of the tooth 208 and the hard metal cutting edge 216 of the tooth Z4 are provided with the chamfers F1.8 oriented in the direction of the longitudinal axis 120. Analogously to the first embodiment, the chamfers F5 8 each have approximately the same width.

In contrast to the first embodiment of the saw blade 100 according to FIGS. 1 to 3, the teeth Z ₃ ,4 are designed without set, ie the teeth Zs,4 are each aligned parallel to the center plane M. This results in a structure of the saw blade 200 that is completely mirror-symmetrical in relation to the center plane M.

FIG. 5 shows a third embodiment of a saw blade 250, which in turn preferably comprises a base section 252 in the form of a band or a rectangular profile. The saw blade 250 with the base section 252 preferably has the center plane M of FIG. 1 with the longitudinal axis 120 lying therein. At the base portion 252 of the saw blade 250 is preferably a plurality of alternately oppositely set teeth, of which only two teeth Zs, 6 with their respective tooth bases 260, 262 or tooth shafts can be seen here. In the region of the respective tooth base upper sides 264, 266 of the teeth Zs, 6, a hard metal cutting edge 274, 276 is preferably in turn arranged or embedded flush in this on the upper side and fastened. The saw blade 250 guided in the saw channel S moves through the workpiece W in the cutting direction 198 of FIG.

In contrast to the first two embodiments of the saw blades 100, 200 from FIGS. 1 to 4, the hard metal cutting edges 274, 276 and the tooth base tops 264, 266 of the teeth Zs, 6 preferably have no continuous, flat or planar chamfers, but rather continuous convex curves Ki 4 up. The continuous convex curves KI, ₂ are preferably formed on both sides of the tooth Z5, and the convex curves K ₃ , 4, continuous on both sides, are formed on the tooth Ze.

The convex roundings KI,...,4 formed on both sides of the hard metal cutting edges 274, 276 and the tooth bases 260, 262 or the tooth base upper sides 264, 266 of the teeth Zs, 6 preferably run at least approximately parallel to the longitudinal axis 120. The hard metal cutting edges 274, 276 close preferably in turn flush with the respective tooth bases 260, 262 of the teeth Zs, 6 on both sides.

The convex curves KI, K4 lying on the outside in relation to the central plane M preferably have radii RI, ₂ of the same size. The same applies to the radii of the inner convex curves K ₂ ,3 of the teeth Zs,e, which are not indicated for the sake of a better overview of the drawing. Deviating from this, the radii Ri 4 of the convex curves K1 4 can all be of the same size or, if necessary, can be dimensioned differently for each tooth or individually for each tooth.

6 shows a fourth embodiment of a saw blade 300 with a base section 302. Two teeth Z1.8 with their respective tooth bases 310, 312 are illustratively formed on the base section 302 of the saw blade 300. FIG. In the region of the tooth base upper sides 314, 316 of the teeth Z1, 8, which are assigned to the tooth bases 310, 312, hard metal cutters 324, 326 are preferably arranged or embedded flush in them and fastened on the upper side. The teeth Z?,8 and all other similar teeth of the fourth embodiment of the shown here Saw blade 300 preferably in turn has a set. The structural design of the other teeth of the saw blade 300, not shown, preferably corresponds to the teeth Z1.8 in terms of structural design. The saw blade 250 guided in the saw channel S preferably moves in the cutting direction 198 through the workpiece W.

In contrast to the embodiments of the saw blades described in FIGS. 1 to 5, the hard metal cutting edges 324, 326 and the tooth base tops 314, 316 of the teeth Z1, 8 of the saw blade 300 which are flush with them preferably have continuous, flat or planar bevels Fg .12, whose widths are preferably of different sizes. The chamfers Fg, i2 lying on the outside in relation to the central plane M preferably each have the same width, only the width B3 of the chamfer Fg being designated for the sake of a better graphic overview. The same applies to the widths of the two inner bevels Fio.n, of which only a width B4 of the bevel F10 of the tooth Zs is designated. Preferably, the widths of the inner chamfers F,n of the teeth Z?,8 are each smaller than the widths of the outer chamfers Fg,i2, so that the width B3 of the outer chamfer Fg illustratively has a significantly larger width compared to the width B4 of the internal chamfer F10 has.

The bevels Fg .12 provided on both sides on the hard metal cutting edges 324, 326 and the tooth bases 310, 312 or the tooth base upper sides 314, 316 of the teeth Z?, 8 preferably run approximately parallel to the longitudinal axis 120. The

Carbide cutting edges 324, 326 are preferably in turn flush on both sides with the respective tooth bases 310, 312 of the teeth Z1, 8, which results, among other things, in their high mechanical robustness and durability.

Fig. 7 shows a fifth embodiment of a saw blade 350, which preferably has a base portion 352, on the illustrative three teeth Zg. n are formed, the constructive design, in particular the tooth geometry, corresponding to the shape of the teeth of the first embodiment of the saw blade from FIGS. 1 to 3 , merely by way of example. The teeth Zg . n can optionally also have convex curves and/or chamfers with different widths analogous to the teeth of the first four embodiments described above. The saw blade 350 is guided in the cutting direction 198 through the workpiece to be machined, but not shown here. In contrast to the embodiments described in Fig. 1 to Fig. 6, the tooth Zu is preferably unset or aligned parallel to the center plane M, while the teeth Zg following it counter to the cutting direction 198 are set opposite to one another and thus a first set sequence 390 realize. As a result of the setting, the teeth Zg. are bent out of the center plane M of the base section 352 of the saw blade 350 in opposite directions. The setting sequence 390 preferably repeats itself over an entire length of the saw blade 350 .

Fig. 8 shows the three teeth Zg n of the saw blade 350 of Fig. 7. The saw blade 350 is located in the saw channel S of the workpiece W. The saw blade 350 with the base section 352 is constructed symmetrically to the center plane M with the longitudinal axis 120 running therein . The tooth Zu of the saw blade 350 is unset, whereas the teeth Zg immediately following it counter to the cutting direction 198 are set opposite to each other at a first setting angle a. The shape of the teeth Zg n and their respective structural design with three tooth bases 360, 362, 364 and the hard metal cutting edges 374, 376, 178 preferably in turn corresponds to the structural design of the teeth of the first embodiment of the saw blade 100 according to FIGS 3.

Due to the design of the teeth Zg n according to the invention, a saw channel base 392 is preferably largely smooth and free of burrs and is therefore stress-free. As a result, among other things, the tendency to form cracks in the saw channel S and thus within the workpiece W can be significantly weakened.

Fig. 9 shows a sixth embodiment of a saw blade 400, which preferably has a base section 402, on which five teeth Z12 ie are formed here by way of example, the geometry of which is only an example of the structural design of the teeth of the first embodiment of the saw blade 100 from Fig. 1 to 3 corresponds. In addition, the teeth Z12 ie can also be designed with convex curves and/or with chamfers of different widths. The saw blade 400 with the base section 402 has the center plane M with the longitudinal axis 120 lying therein. The saw blade 400 is guided in the cutting direction 198 through the workpiece to be machined, which is not shown here.

In contrast to the fifth embodiment of the saw blade 350 according to FIGS. 7 and 8, the tooth Zis that is furthest in front in the cutting direction 198 is unset here, while the two teeth Zu, 15 that directly follow it opposite to the cutting direction 198 are opposite to each other in one first setting angle (cf. FIG. 10) are set. The other two teeth Zi2,i3 following the teeth Zi4,i5, on the other hand, are set in opposite directions to one another at a second set angle, as a result of which the teeth Z12 16 form a second set sequence 490. The second set sequence 490 preferably repeats itself over the entire length of the saw blade 400 .

10 shows the five teeth Zi2,...ie of the saw blade 400 of FIG running longitudinal axis 120 constructed. The tooth Z16 of the saw blade 400 lying furthest in front in the cutting direction is unset, whereas the teeth Z15, 15 immediately following it counter to the cutting direction 198 are set opposite to one another at the first setting angle a. The two teeth Zi2, i3 immediately following the teeth Zu, 15 in the cutting direction 198 are set opposite to one another at the second setting angle β. The second twist angle β is preferably dimensioned larger than the first twist angle a in order to implement the second twist sequence 490 .

The shape of the teeth Zi2,...ie and their respective structural design corresponds only by way of example to the teeth of the first embodiment of the saw blade 100 according to FIGS Set sequence 490 characterized by a further increased smoothness and an extensive freedom from stress cracks. 11 shows the tooth Zi of the saw blade 100 from FIGS. 1 to 3 equipped with the hard metal cutting edge 114, which illustratively has a thickness D, the width Bi of the bevel Fi and a width Bs of the bevel F2 preferably being approximately the same size . The widths Bi,s preferably each correspond to approximately 10% to 40% of the thickness D of the tooth Z1. The widths Bi,s of the chamfers Fi,2 are preferably between 20% and 35% of the thickness D of the tooth Z1, in each case including assigned interval limits. Two bevel angles yi,2 of the two bevels Fi,2 of the tooth Z1 are preferably between 10° and 60° in relation to the upper side 170 of the hard metal cutting edge 114 or the horizontal, preferably between 20° and 45°, each including assigned interval limits. The dimensioning ratios mentioned above preferably apply correspondingly to all other teeth of the saw blade 100.

FIG. 12 shows the tooth Z5 of the saw blade 250 according to FIG. 5, equipped with the hard metal cutting edge 274, which illustratively has the thickness D like the tooth Z1 according to FIG. The radii RI, ₃ of the convex curves KI, ₃ are preferably approximately between 10% and 40% of the thickness D, preferably 20% to 35% of the thickness D, each including assigned interval limits.

FIG. 13 shows the tooth Z7 of the saw blade 300 according to FIG. 6 equipped with the hard metal cutting edge 324, which illustratively has the thickness D like the tooth Z1 according to FIG. The widths of the chamfers Fg. are preferably dimensioned differently. The ratio between the widths B ₃ ,4 and the thickness D of the tooth Z7 preferably corresponds to the dimension ratio between the widths Bi,s of the chamfers Fi, ₃ and the thickness D of the tooth Z1 of FIG. 11. The sizes of the chamfer angles 73.4 of the chamfers Fg. of the tooth Z7 preferably correspond accordingly to the sizes of the chamfer angles yi,2 of the chamfers Fi,2 of the tooth Z1 from Fig. 11.

The width B4 of the bevel F10 of the tooth Z7 of the saw blade 300 is preferably selected to be larger in relation to the width _B3 of the bevel Fg of the tooth Z7. The bevel angle Y4 of the bevel F10 is preferably not smaller than the bevel angle ys of the bevel Fg. The dimensional relationships explained in the description of FIGS. 11 to 13 preferably apply to all teeth of the respective embodiment of the saw blade according to the invention.

The six embodiments of the saw blades 100, 200, 250, 300, 350, 400 described above are preferably used in motor saws or hand saws of all kinds provided. With the help of the saw blades 100, 200, 250, 300, 350, 400, a workpiece made of plastic, wood, a mineral material or metal can be machined. The saw blades 100, 200, 250, 300, 350, 400 can be used in a straight line, for example. In such a constellation, the saw blades 100, 200, 250, 300, 350, 400 can be used, for example, in motorized jigsaws, hand hacksaws, handsaws, veneer saws or the like. Furthermore, the saw blades 100, 200, 250, 300, 350, 400 can also be used in a circular configuration with radially outwardly oriented teeth in motor-driven table or hand-held circular saws.

Furthermore, it is possible to bring the saw blades 100, 200, 250, 300, 350, 400 into a hollow-cylindrical shape, with free ends of the saw blade being connected firmly to one another in a suitable manner in such a constellation to create the endless geometry. In this way, for example, a highly efficient so-called hole saw (circle or ring cutter), which is not shown in the figures, can be provided. In addition, the saw blades 100, 200, 250, 300, 350, 400 can be used in a motorized band saw, for example.

Claims

Expectations

1 . Saw blade (100, 200, 250, 300, 350, 400) having a multiplicity of wavy shaped teeth (Zi ) which are attached to a continuous base section (102, 202, 252, 302, 352, 402) of the saw blade (100, 200, 250, 300, 350, 400) are formed, the teeth (Zi) each having an associated tooth base (140, 142, 260, 262, 360, 362, 364, 310, 312) with a tooth base top (150, 152, 206, 208, 264, 266, 314, 316) and a hard metal cutting edge (114, 116, 214, 216, 274, 276, 324, 326, 374, 376, 378) arranged thereon, characterized in that each tooth base (140, 142 , 260, 262, 360, 362, 364, 310, 312) in each case along a longitudinal axis (120) of the base section (102, 202, 252, 302, 352, 402) flush on both sides with the hard metal cutting edge (114, 116, 214) arranged thereon , 216, 274, 276, 324, 326, 374, 376, 378) and each carbide tip (114, 116, 214, 216, 274, 276, 324, 326, 374, 376, 378) and each tooth base top (150, 152, 206, 208, 264, 266, 314, 316) two in the Has chamfers (Fi 12) and/or convex curves (K1 4) extending essentially along the longitudinal axis (120) of the base section (102, 202, 252, 302, 352, 402), wherein the teeth (Zi ) are designed without set and/or set are.

2. Saw blade according to claim 1, characterized in that the bevels (Fi, 2, 3, 4) of each hard metal cutting edge (114, 116) have essentially the same width (61,2,5).

3. Saw blade according to claim 1, characterized in that the bevels

(Fg 12) of each tooth (306, 308) have a different width (63.4).

4. Saw blade according to claim 1, characterized in that the convex curves (K1 4) have a substantially equal radius (RI, 2). Saw blade according to one of the preceding claims, characterized in that in each case two teeth (Zi, 2) directly following one another along the longitudinal axis (120) are set opposite to one another. Saw blade according to one of Claims 1 to 4, characterized in that at least one tooth (Zu) is unset and the two teeth (Zg.io) immediately following it along the longitudinal axis (120) are set opposite to one another and this set sequence (390) repeated along the longitudinal axis (120) across all teeth of the saw blade (350). Saw blade according to one of Claims 1 to 4, characterized in that at least one tooth (Z ) is unset and two further teeth (Zu, 15) immediately following it along the longitudinal axis (120) are set opposite to one another at a first setting angle (a). and two further teeth (Z12 3) immediately following the teeth (Zi4,is) set in the opposite direction along the longitudinal axis (120) in the first setting angle (a) are set in opposite directions to one another at a second setting angle (ß) and this setting sequence (490) repeated along the longitudinal axis (120) across all teeth (Z12) of the saw blade (400). Saw blade according to Claim 7, characterized in that the first setting angle (a) is smaller than the second setting angle (ß). Saw blade according to one of Claims 1 to 7, characterized in that the hard metal cutting edges (114, 116) have a tooth tip (158, 160) above a concave chip space (154, 156) pointing in the cutting direction (198) of each tooth (Z1 2) form. Saw blade according to one of Claims 1 to 8, characterized in that the hard metal cutting edges (114, 116, 214, 216, 274, 276, 324, 326, 374, 376, 378) are fixed to the tooth base (140, 142, 260, 262 , 360, 362, 364, 310, 312) of the teeth (Z1 w) are connected, in particular thermally joined to them. Saw blade according to one of the preceding claims, characterized in that the base section (102, 202, 252, 302, 352, 402) of the saw blade (100, 200, 250, 300, 350, 400) is provided with a hardened steel and the hard metal cutting edges (114 , 116, 214, 216, 274, 276, 324, 326, 374, 376, 378) are preferably formed with a tungsten carbide-cobalt cemented carbide. Hole saw, characterized in that it is formed with a saw blade (100, 200, 250, 300, 350, 400) according to at least one of Claims 1 to 11 that is essentially bent into a ring.

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