EP3043962B1 - Cutting tool - Google Patents

Description

The invention relates to a cutting tool with a plurality of segment cutting discs.

In the manufacture of wall slits e.g. for the laying of electric cables, it is good practice to first set two parallel cuts in the wall by means of a cutting disc. Between the cuts, however, initially remains a central bar, which is then remove consuming with a chisel.

From the EP 2 193 882 B1 Cutting discs are known for creating wide notches in walls of more than 5mm. The circumference of a master blade is provided with several cutting segments. One segment gap remains between two cutting segments. To create a widened section, the cutting segments are offset with respect to a central cutting plane. With such cut-off wheels can be placed on the actual wall thickness of the cutting disc quite wide cuts. If you use these blades for setting the cuts in the wall, so remains a smaller and thus easier to remove center bar. Although the cutting width of such cutting discs could be increased by widening the cutting segments again. However, such broadening is limited, since the risk of clogging the cutting edge with removed material increases with the width of the cutting edges.

In the DE 20 2012 002 545 U1 a cutting tool is described, which comprises three segmented cutting discs, each with a master blade and distributed over the circumference of the master blade cutting segments. The cutting discs are arranged insoluble coaxial side by side. In such a cutting tool identical cutting discs are always used. However, it has been shown that the cutting discs of such a cutting tool wear different degrees. If one of the cut-off wheels is worn, the entire cutting tool can no longer be used. This is all the more regrettable because the remaining, not yet worn cut-off wheels remain functional on their own but still become useless. In this respect, this problem is accompanied by a certain waste of raw materials, which are quite expensive especially in the case of diamond cutting discs. It is therefore an object of the present invention to improve an aforementioned cutting tool in terms of the problem addressed.

The object underlying the invention is achieved by a cutting tool according to claim 1; preferred embodiment will become apparent from the dependent claims.

The cutting tool according to the invention comprises a plurality of cutting discs, in particular diamond cutting discs. The cutting discs are arranged coaxially along a common axis of rotation adjacent to each other. Each blade comprises a master blade having a plurality of cutting segments distributed about the circumference of the blade, each blade defining a central cutting plane. In this respect, the cutting discs are segmented cutting discs. At least some of the cutting segments protrude axially out of the central cutting plane. Between two circumferentially adjacent cutting segments of a cutting disc each leaves a segment gap. The cutting segments are radially on the outside of a support area, in particular made of sheet metal applied. At least one of the cutting segments, which is arranged in an axially first position, is enlarged relative to a second cutting segment, which is arranged in a second axial position. The cutting segment is understood to mean, in particular, the region of the cutting disk which is fastened radially on the outside to a carrier region and comprises a grinding-active material.

The core of the invention is based in particular on the knowledge that cutting segments wear out at different speeds; the cutting segments at identical axial positions, however, wear out substantially uniformly. The solution, therefore, is to selectively reinforce the cutting segments individually such that the amplification magnification affects only those few cutting segments that are subject to increased high wear. It is therefore deliberately refrained from increasing its life by a sweeping reinforcement of the cutting tool. On the contrary, individual segments are selectively enlarged relative to other segments in order to match the life span of all segments. Particularly heavily loaded segments can be additionally reinforced; particularly lightly loaded segments can also be reduced in their resistance, which has a direct effect on the cost of einzusetzendem raw material. On the basis of test series, it can be determined to what extent an increased formation of individual segments has to be made, so that the Cutting segments are worn as evenly as possible at all positions or have the same life as possible. The aim is therefore that the segments also have a largely identical life in view of the different loads.

It is preferably provided that the at least one first cutting segment and the at least one second cutting segment are arranged at axially opposite outermost axial positions of the cutting tool. In other words, the axially outermost cutting segments on the one outermost axial side are reinforced with respect to the axially outermost cutting segments on the other outermost axial side. The meaning of this measure does not seem obvious at first, since the load at both axial outer positions of the cutting tool appear identical. This is usually not the case. Due to the asymetric handling of the cutting tool and the machine tool used, it can be seen that an outermost axial position can be much heavier loaded than the other outermost axial position. This may be due to the handedness, that is, e.g. As a matter of principle, the right-hander should exert greater force on the machine on the right-hand side than on the left-hand side. Therefore, it can also be provided that the cutting tools are expressly designed for left-handers and expressly for right-handed people, then in each case different cutting segments are to be reinforced.

In a preferred embodiment, one of the axially outer cutting discs, with a greater thickness (ie, the cross-sectional thickness) is equipped as the other of the axially outer cutting discs. Although this overall asymmetry in the cutting tool is made; However, the asymmetry again compensates for an asymmetrical operation of the operator. Due to the fact that most operators are right-handed, for example, the right cutting wheel wears out more heavily than the left outer cutting wheel. For left-handers, this is correspondingly reversed, as already stated. For the increase in the thickness of the cutting disc, it is sufficient if only the segments are increased in their cross-sectional thickness.

Furthermore, it is preferred that the outer cutting discs have a greater thickness than the inner cutting discs. Basically, it should be noted that the outer segments are usually more stressed than the inner segments. The outer segments bring the outer cut into the solid masonry. The inner segments are intended to interpose the remaining central web to remove the outer cuts. In contrast to solid masonry, however, only a small amount of labor is required when removing the center bar, since the stability of the central bar is already reduced by the lack of lateral support. Also for this it is sufficient that the segments of the outer cutting discs are only increased in their cross-sectional thickness.

An enlarged trained segment can be designed trapezoidal. The bases of the trapezium are approximately radially aligned and approximately parallel to each other (the angular offset due to the different circumferential position is neglected). The arranged in the direction of rotation front side is longer than the rear side arranged base. The radially outer leg represents a circular arc section. The second leg then results from the connection of the radially inner ends of the bases. It has also been shown in this design of the segments that the reduced trained segments are, so to speak, in a kind of shadow of the enlarged formed segments. This results in a more favorable distribution of wear on the individual segments.

Figur 1

ein erfindungsgemäßes Schneidwerkzeug

1. a) in Seitenansicht,
2. b) in Frontansicht,
3. c) in perspektivischer Darstellung;

Figur 2

ein Teilquerschnitt durch eine Anzahl von Schneidsegmenten eines alternativen Schneidwerkzeugs.

The invention will be explained in more detail below with reference to the figure

FIG. 1

an inventive cutting tool

1. a) in side view,
2. b) in front view,
3. c) in perspective;

FIG. 2

a partial cross section through a number of cutting segments of an alternative cutting tool.

In FIG. 1 an inventive cutting tool 1 is shown. This comprises three cutting discs 2 ', 2 ", 2"'. The cutting discs 2 'and 2'"are the axially outer cutting discs; the cutting disc 2" is the internal cutting disc. If, in an alternative embodiment, the cutting tool has only two cutting discs, then both cutting discs are the axially outer cutting discs; It is then provided no internal cutting discs. Cutting tools with more than three cutting discs comprise several internal cutting discs.

The first outer cutting disc 2 'has two different types of cutting segments, namely left cutting segments 4 _L ' and right projecting cutting segments 4 _R '. Both types of cutting segments protrude from the cutting plane, since a respective carrier region 8, to which the segments 4 are fastened, are bent over the master blade 5, which defines the central cutting plane E. However, the support area need not be bent out, but can also be held by other means at an angle to the cutting plane E 'on a common master sheet 5; however, it is essential that the cutting segments 4 'all protrude axially from the central cutting plane E'. This also applies to the other cutting discs. The left and right projecting cutting segments are arranged alternately in the circumferential direction.

The protruding to the left cutting segments 4 _L 'due to their axial outward protruding from the outermost central cutting plane E' at the same time also the axially outer cutting segments of the entire cutting tool 1 and are in the following also with the reference numeral 4 _A 'provided (Index A for outside ). In contrast, the right projecting cutting segments 4 _R 'of the first cutting disc 4' are internal cutting segments, which are also provided with the reference numeral 4 _I '(index I for inside). Analogously to the separating disk 2 ', the other two cutting disks 2 "and 2'" have cutting segments 4 _L ', 4 _L "and 4 _R ', 4 _R ", which are either left or right from the respective middle cutting planes E ". and E '"stand out. In contrast to the cutting disk 2 ', however, the cutting segments 4 _R '"protruding to the right represent the axially outer cutting segments 4 _A "'of the cutting tool 1, which are additionally designated by the reference numeral 4 _A "' 4 _L ", 4 _R " of the middle cutting disc 2 "are all also referred to as internal cutting segments 4 _I ", regardless of whether they protrude to the left or to the right, since they are not axially outer cutting segments of the cutting tool 1.

The axially outer cutting segments 4 _A 'and 4 _A '"are the most heavily loaded cutting segments of the cutting tool 1. These are formed enlarged relative to the other segments FIG. 1b As can be seen, these outermost cutting segments 4 _A ', which also apply equally to the unrecognizable cutting segments 4 _A '', have a trapezoidal shape in side view A base side 6 of this trapezoid facing in the direction of rotation U is longer than a rearward one in the direction of rotation Bottom side 7 of the trapezium, the thighs become one formed by the peripheral boundary edge 10 of the cutting segment 4; on the other hand by the dividing line 11 between carrier region 8 and segment 4, thus Verbindungsunbgslinie the other of the two inner ends of the bases 6 and 7. The inner segments 4 _I 'are designed substantially annular, with a constant radial dimension over the circumferential extent. The configuration of the inner segments 4 _I ", 4 _I "'of the second and third cutting discs 2 ", 2'" corresponds to the configuration of the inner segments 4 _I ", 4 _I "'of the first cutting disc 2'. The terms radial and parallel are to be interpreted broadly in connection with the trapezoidal design and are intended to indicate the coarse alignment. The terms can also include a slight curvature, so no exactly rectilinear training.

FIG. 2 shows an alternative embodiment, which is largely the embodiment FIG. 1 equivalent. For the sake of simplicity, only cross-sections of three segments per cutting disc are shown, which are representative of all other segments of the respective cutting tool. For further clarification, the cutting segments designated as internal and those designated as external are differently hatched. As a result, it can already be seen pictorially that only a small number of the cutting segments are reinforced.

The representation after the FIG. 2 basically corresponds to a cut, as in FIG. 1 is indicated by the connecting line II-II. Deviating from the embodiment according to FIG. 1 Not only are left and right protruding segments 4 _L and 4 _R available, but also middle cutting segments 4 _M ', 4 _M ", 4 _M "' provided, which are not staggered to the respective central cutting plane E. Such cutting segments are referred to as internal cutting segment 4 _I. The design of the middle cutting segments 4 _M ', 4 _M ", 4 _M " is identical to the other internal cutting segments 4 _I already described. The measures that contribute to the reinforcement of the entire cutting tool, therefore, require only an enlarged training on a fairly small number of segments and are therefore much cheaper to perform, than the overall reinforcement of all cutting discs or all segments of all cutting discs.

Alternatively or in combination, a segment 4 _A compared to another segment 4 _I also be formed reinforced, in which the segments are thicker in cross-section.

LIST OF REFERENCE NUMBERS

1

cutting tool

2

cutting wheel

3

segment gap

4

cutting segment

5

trunk leaf

6

front side

7

back ground side

8th

support region

10

leg

11

leg

e

middle cutting plane

U

direction of rotation

A

axis of rotation

Claims (4)

1. A cutting tool (1) with several cutting discs (2), in particular diamond cutting discs,
   wherein the separating disks (2) are disposed coaxially adjacent to one another along a common axis of rotation (A),
   wherein each cutting disk (2) includes, in turn, a saw-blade body (5) with several cutting segments (4) distributed over the circumference of the saw-blade body (5),
   wherein each saw-blade body (5) defines a central cutting plane (E),
   wherein at least some of the cutting segments protrude axially from the central cutting plane (E),
   wherein a segment finish (3) remains in each case between two cutting segments (4) of a separating disc (2), which are adjacent to one another in a direction of rotation (U),
   characterized in
   that at least a first of the cutting segments, which is disposed in a first axial position, is designed enlarged in comparison a second cutting segment, which is disposed in a second axial position, which deviates from the first axial position.
2. The cutting tool of the preceding claim,
   characterized in
   that all cutting segments (4_A), which are disposed at the first axial position, are identically enlarged in comparison to all cutting segments 4_i, which are disposed at the second axial position.
3. The cutting tool of one of the preceding claims,
   characterized in
   that the first cutting segment (4_A') and the second cutting segment (4_A') are disposed in each case at axially opposite exterior positions of the cutting tool (1).
4. The cutting tool of the preceding claims,
   characterized in
   that in side view, the enlarged cutting segments (6'_A) are trapezoidal, wherein the base sides (6, 7) of the trapeze being radially aligned and the base side (6), disposed at the front in the direction of rotation (U), being longer than the base side (7), which is disposed at the rear.

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