Saw blade

Abstract

A saw blade contains a body, in particular of a hard material, having a cutting portion. The cutting portion has a length and a width and being provided along its length with a plurality of teeth which are formed by a plurality of grooves. Each tooth being formed by at least two grooves. There is a first plurality of grooves, the grooves of which are parallel to each other along a first direction and in that there is a second plurality of grooves, the grooves of which are parallel to each other in a second direction. The first direction and the second direction are inclined to each other such that along the length of the cutting portion at least one of the grooves of the first plurality of grooves is intersected by a groove of the second plurality of grooves.

Claims

1. A saw blade, comprising: a body of a hard material being cemented carbide, the body having a cutting portion, the cutting portion having a length and a width and being provided with a plurality of teeth along the length, the cutting portion having two sides extending parallel to the length and arranged opposite one another, the cutting portion having a plurality of grooves formed therein defining the teeth, each tooth of the teeth being formed by at least two of the grooves, the grooves including a plurality of first grooves, the first grooves being parallel to each other along a first direction and intersecting each of the two sides, the grooves including a plurality of second grooves, the second grooves being parallel to each other in a second direction and intersecting each of the two sides, the first direction and the second direction being inclined to each other such that along the length of the cutting portion at least one of the first grooves is intersected by a second groove of the plurality of second grooves, the at least one of the first grooves and the intersecting second groove each having a rounded groove base and the grooves being formed by grinding, the teeth of the cutting portion being defined by flanks of the grooves.

2. The saw blade according to claim 1, wherein the first direction and the second direction are inclined to a direction that is parallel to the width of the cutting portion and are inclined to a direction that is parallel to the length of the cutting portion.

3. The saw blade according to claim 1, wherein the first direction and the second direction lie in a common plane which is parallel to a plane which is formed by a direction that is parallel to the width of the cutting portion and a direction that is parallel to the length of the cutting portion.

4. The saw blade according to claim 1, wherein along the length of the cutting portion, the first grooves of the plurality of first grooves which are intersected by the second grooves of the plurality of second grooves are alternated with the first grooves of the plurality of first grooves which are not intersected by a second groove of the plurality of second grooves.

5. The saw blade according to claim 1, wherein along the length of the cutting portion at least two adjacent the first grooves of the plurality of first grooves are intersected by one second groove of the plurality of second grooves.

6. The saw blade according to claim 1, wherein an angle between the first direction and the second direction lies in a range of about 1 to about 90.

7. The saw blade according to claim 6, wherein the angle lies in a range of about 10 to about 30.

8. The saw blade according to claim 1, wherein an angle between the first direction and a direction that is parallel to the width of the cutting portion lies in a range of about 0 to about 90 and/or an angle between the second direction and the direction that is parallel to the width of the cutting portion lies in a range of about 0 to about 90.

9. The saw blade according to claim 8, wherein the angle between the first direction and the direction that is parallel to the width of the cutting portion lies in a range of about 5 to about 45 and/or the angle between the second direction and the direction that is parallel to the width of the cutting portion lies in a range of about 5 to about 45.

10. The saw blade according to claim 1, wherein a distance between adjacent ones of the second grooves is larger than a distance between adjacent ones of the first grooves.

11. The saw blade according to claim 1, wherein the first direction and the second direction are chosen such that along the length of the cutting portion, the teeth of a first type result which are truncated on one of their lateral sides and the teeth of a second type result, which alternate with the teeth of the first type and which are truncated on the other of their lateral sides, truncations being adjacent to a longitudinal edge of the cutting portion running along the length of the cutting portion, such that all the teeth are of asymmetrical shape with respect to a direction that is parallel to the length of the cutting portion.

12. The saw blade according to claim 1, wherein a cross-section of the body at least over a section of the length of the cutting portion widens into a direction of the teeth.

13. The saw blade according to claim 1, further comprising a carrier; and wherein the body is affixed to the carrier.

14. The saw blade according to claim 13, wherein the carrier is made of steel.

15. The saw blade according to claim 1, wherein a distance between the second grooves is double a distance between the first grooves.

16. A saw blade, comprising: a body having a cutting portion, the cutting portion having a length and a width and being provided with a plurality of teeth along the length, the cutting portion having two sides extending parallel to the length and arranged opposite one another, the cutting portion having a plurality of grooves formed therein defining the teeth, each tooth of the teeth being formed by at least two of the grooves, the grooves including a plurality of first grooves, the first grooves being parallel to each other along a first direction and intersecting each of the two sides, the grooves including a plurality of second grooves, the second grooves being parallel to each other in a second direction and intersecting each of the two sides, the first direction and the second direction being inclined to each other such that along the length of the cutting portion at least one of the first grooves is intersected by a second groove of the plurality of second grooves for defining one of the teeth, two of the first grooves being adjacent one another for defining another one of the teeth therebetween.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 shows a cutting portion of a first embodiment of the invention

(2) FIG. 2 shows a cutting portion of a second embodiment of the invention

(3) FIG. 3 shows a cutting portion of a third embodiment of the invention

(4) FIG. 4 shows a cutting portion of a fourth embodiment of the invention

(5) FIG. 5 shows a saw blade according to the invention

(6) FIG. 6 shows geometrical features of a cutting portion according to the invention

(7) FIG. 7 shows a first step of a method to produce an inventive saw blade

(8) FIG. 8 shows a further step of a method to produce an inventive saw blade

(9) FIG. 9 shows a cutting portion of a fifth embodiment of the invention

(10) FIG. 10 shows a cutting portion of a sixth embodiment of the invention

(11) FIG. 11a,b show a schematic image of a grinding wheel that could be used for the manufacture of a saw blade in perspective and in detail

(12) FIG. 12 shows a schematic cross-section of an inventive saw blade in the region of the cutting portion

DETAILED DESCRIPTION OF THE INVENTION

(13) FIG. 1 shows a cutting portion 3 of a saw blade 1 (cf. FIG. 5) having a width W. Only part of the length L is shown. In a body 2 of hard material a first plurality of grooves 4 running parallel to direction d.sub.1 has been ground and a second plurality of grooves 5 running parallel to direction d.sub.2 has been ground.

(14) Both directions, d.sub.1 and d.sub.2, are inclined with respect to each other and with respect to a direction d.sub.W that is parallel to the width W of the cutting portion 3 and with respect to a direction d.sub.L that is parallel to the length L of the cutting portion 3.

(15) Teeth of the cutting portion 3 are being formed as flanks of the grooves 4, 5. It can be seen that in this embodiment lateral sides of adjacent teeth which together form a groove 4, 5 are either both faceted or are both formed by a single plane surface.

(16) It can be seen that in the embodiment of FIG. 1 the first direction d.sub.1 and the second direction d.sub.2 are chosen such that along the length L of the cutting portion 3, teeth of a first type result which are truncated on one of their lateral sides and teeth of a second type result, which alternate with teeth of the first type and which are truncated on the other of their lateral sides, the lateral sides being adjacent to an imaginary longitudinal edge of the cutting portion 3 running along the length L of the cutting portion 3, and such that all teeth are of asymmetrical shape in a direction d.sub.L that is parallel to the length L of the cutting portion 3. An advantage of such an arrangement lies in the fact that the cutting process is being shared between the teeth of the first and the second type in that, in one direction of the cutting process only the first or second type teeth are engaging the material to be cut and in the other direction of the cutting process the other one of the first or second type teeth are engaging the material to be cut, provided there is a reciprocating motion of the cutting portion 3 along its length L. Another advantage lies in the fact that chip removal is facilitated.

(17) In the embodiment of FIG. 1, only every second groove 4 of the first plurality of grooves 4 is intersected by a groove 5 of the second plurality of grooves 5.

(18) In the embodiment of FIG. 2, two grooves 4 of the first plurality of grooves 4 which are separated from each by a single groove 5 of the second plurality of grooves 5 are intersected by this single groove 5 of the second plurality of grooves 5 at intersections 45, one in a region near the one portion of the cutting portion 3 and the other in a region near the other portion of the cutting portion 3, both regions being separated from each other by a little less than the width W of the cutting portion 3.

(19) The resulting groove/tooth characteristic provides for aggressive cutting performance and thus high feed rates.

(20) In the embodiment of FIG. 3, three adjacent grooves 4 of the first plurality of grooves 4 are being intersected and thus connected by a single groove 5 of the second plurality of grooves 5.

(21) In the present example the directions d.sub.1 and d.sub.2 are both chosen at large angles. It has been found that the resulting groove/tooth characteristic shows low friction. This leads to reduced power consumption and reduced frictional heat.

(22) In the embodiment of FIG. 4, similar to the embodiment of FIG. 1, only every second groove 4 of the first plurality of grooves 4 is intersected by a groove 5 of the second plurality of grooves 5. It can be seen that in this embodiment lateral sides of adjacent teeth which together form a groove 4, 5 are either both faceted or are both formed by a single plane surface. The embodiment represents a robust tooth geometry with good lifetime.

(23) FIG. 5 shows part of an inventive saw blade having a cutting portion 3 which is formed on a body 2 of hard material, the body 2 of hard material being welded to a carrier 6 made of steel. In FIG. 5 there are shown, in exemplary manner also applicable to the other embodiments, the feed direction F and the oscillation direction O.

(24) During operation, the saw blade oscillates or reciprocates along the oscillation direction O. Commonly one speaks of oscillation when the displacements are very small, typically in the range of a few millimeters, while in case of reciprocating saws the displacements measure several millimeters.

(25) In use, the saw blade moves through a workpiece in feed direction F at a certain feed rate.

(26) In FIG. 6 the different directions that occur with respect to the invention are being shown with respect to a schematic depiction of the cutting portion 3. The cutting portion is shown in a top view, that is, parallel and opposite to a later feed direction.

(27) FIG. 7 shows the result of a first and a second step of a method to produce a saw blade, in particular a saw blade according to at least one of discussed embodiments, by grinding a surface of a body 2 of hard material to form a plurality of teeth, the surface having a length L and a width W, the method using a grinding tool having a plurality of spaced grinding surfaces which are parallel to each other along a grinding direction d.sub.g. If a saw blade made of a body 2 of hard material affixed to a carrier 6 is being used, the grinding can take place after the body 2 of hard material has been affixed to the carrier 6.

(28) In the first step the grinding tool is applied to the surface in a first grinding direction d.sub.g1 that is inclined to a direction d.sub.W which is parallel to the width W of the surface. A first subset of the first plurality of equidistant, parallel grooves 4 is being ground, the grooves 4 having a distance 2*G.sub.1 from each other.

(29) Then, as a second step, the grinding tool is being offset with respect to the surface along the length L of the surface, the offset corresponding to half of a distance between the spaced grinding surfaces of the grinding tool, that is half tooth pitch. A second subset of the first plurality of equidistant, parallel grooves 4 is being ground, the grooves 4 having a distance G.sub.1 from each other. The situation shown in FIG. 7 arises (however, not all of the grooves 4 ground along the length L are being shown).

(30) As shown above, through a further grinding operation offset to the first grinding operation the resulting tooth pitch can be halved as it would result from one grinding operation alone. It shall be noted that the offset can be chosen other than half the distance between the spaced grinding surfaces of the grinding tool, that is, other than half tooth pitch, resulting unequally spaced grooves 4 respectively teeth.

(31) In a third step (FIG. 8) the grinding tool is inclined to be parallel to a second grinding direction d.sub.g2 that is inclined to the direction d.sub.W which is parallel to the width W of the surface and is inclined to the first grinding direction d.sub.g1. In FIG. 8 not all of the grooves 4, 5 which are ground along the length L are being shown.

(32) Production of the saw blade is now finished. In this embodiment only three grinding steps (first step, second step and further step) had to be used.

(33) FIG. 9 shows an embodiment of an inventive saw blade with a convexly curved cutting portion 3.

(34) FIG. 10 shows an embodiment of an inventive saw blade with a concavely curved cutting portion 3.

(35) FIGS. 11a and 11b show an example for a grinding tool 7 which can be used in a method according to the invention with a plurality of grinding surfaces. The grinding surfaces are parallel to each other and are equally spaced along an axis of the grinding tool 7.

(36) FIG. 12 shows a cross-section of an inventive saw blade 1 in the region of the cutting portion 3 (the individual grooves 4, 5 and teeth which are of course present in the body 2 of hard material are not shown). It can be seen that in this embodiment the cross-section of the body 2 of hard material widens into a direction of the teeth, thus creating a side clearance with the saw blade.

REFERENCE SIGNS

(37) 3 saw blade 2 body of hard metal 3 cutting portion 4 grooves of the first plurality of grooves 5 grooves of the second plurality of grooves 6 carrier 7 grinding tool L length of cutting portion W width of cutting portion F Feed direction O Oscillation direction d.sub.1 first direction (of grooves of the first plurality of grooves) d.sub.2 second direction (of grooves of the second plurality of grooves) d.sub.W direction that is parallel to the width of the cutting portion d.sub.g1 first grinding direction d.sub.g2 second grinding direction angle between the first direction d.sub.1 (or first grinding direction d.sub.g1) and the second direction d.sub.2 (or second grinding direction d.sub.g2) G.sub.1 distance between grooves of the first plurality of grooves G.sub.2 distance between grooves of the second plurality of grooves