DESCRIPTION

Field of application

The present invention is generally applicable to the field of mechanical machining, and in particular, the present invention relates to a cutting tool.

Background art

In the field of cutting metallic materials and, in particular, in the use of band saw blades, cutting bands are commonly used, i.e. blades constructed with a harmonic steel band that is toothed on the cutting side and smooth on the opposite side.

Typically, such blades are used for the cutting and separation of metals and metal alloys of any size and shape such as bars, profiles, and plates. However, the use of band saw blades for cutting special alloys involves particularly long and expensive operations, due to the strong resistance to chipping of the alloys themselves.

In order to overcome these drawbacks, in the prior art blades are produced in which an insert is welded on the cutting tip, made of hard material, typically hard metal (carbide) or ceramic material (cermet), which will subsequently be given a geometric shape through the grinding of its sides.

In addition, generally, to improve the cutting capacity, the arrangement of the band toothing is carried out, commonly called setting, which consists of the alternating bending of the teeth so as to create, during the separation process, the space interposed between the band surface and the cut surface on both sides. In other words, the base of the teeth is bent to the right and to the left with respect to the longitudinal plane of the band saw blade body, according to an arrangement order suitable for the section to be divided.

However, despite the above technical measures for the production of band saw blades for cutting very resistant special alloys, the durability of the blades is still quite limited.

In fact, the hard metal ground tips are subjected to very disadvantageous cutting conditions, for example, due to the high development of heat that is generated in the chip formation during cutting. In addition, the phenomenon of wear of the tips due to adhesion and abrasion quickly deteriorates the chip formation capacity with an inevitable and rapid decrease in the feed speed and a constant increase in noise. At a certain point, in fact, the cutting strength, understood as the sum of the individual pulling load forces on the teeth simultaneously in contact, will be such as to compromise the torsional rigidity of the band saw blade and, consequently, a non-straight cut will result or the band itself will lock.

Moreover, in the blades set by the arrangement, the aforementioned stresses are such as to inevitably cause lateral bending of the teeth, with the consequent alteration of the inclination and modification in the division of the chip of the predetermined cutting channel.

In addition to this, the setting is carried out by means of tools, typically punches, which allow the base of the teeth to be bent by inclining it according to torsion. However, such an arrangement technique may be inaccurate, or may otherwise present difficulty in bending the teeth at predetermined angles.

In addition, during the setting process it is particularly difficult to form different inclinations of the teeth, to obtain greater solutions of cutting geometry.

Additionally, the bending involves yielding at the base of the tooth, which weakens the section along the profile of the toothing, thus increasing the possibility of breakage also caused by impurities and inclusions in the cut material.

Presentation of the invention

The object of the present invention is to provide a cutting tool which allows the drawbacks highlighted above to be at least partially overcome.

In particular, the object of the present invention is to provide a cutting tool that allows cutting also of hard materials such as, for example, superalloys, wear- resistant steels and nickel alloys of any size and subjected to any heat treatment.

Another purpose of the present invention is to provide a cutting tool that is suitable for sustaining higher stresses than equivalent tools in the known art.

In other words, the object of the present invention is to provide a cutting tool whose cutting teeth are able to bear greater loads without twisting.

A further object of the present invention is to provide a cutting tool that allows the stresses sustained to be distributed in a better way compared to the equivalent tools present in the prior art.

Another object of the present invention is to provide a tool which, at the same cutting speed as the other known tools, greatly reduces the processing time and at the same time always maintains a lower noise level.

A further purpose of the present invention is to provide a cutting tool whose groove limits friction.

Another object of the present invention is to provide a tool that, at the same cutting speed as the other known tools, reduces the sonic levels of the harmonics, thus avoiding splinters on the cutting edges, especially during the initial running- in phase.

Said objects, as well as others which will become clearer below, are achieved by a cutting tool in accordance with the following claims, which are to be considered an integral part of the present patent.

In particular, the cutting tool comprises at least one substantially laminar support body, a plurality of cutting teeth, having at least one support base emerging from the support body, and at least one cutting tip stably coupled to the support base itself.

Said plurality of teeth comprises a subset of asymmetric teeth, in which the support base is substantially comprised in a plane longitudinal to the support body and the cutting tip is set at least by means of a lateral grinding thereof so as to shape the inclination and/or the conicity of at least one flank thereof by inclining it with respect to said plane to widen and shape the cutting groove.

Advantageously, the cutting tip allows the tool of the invention to also cut hard materials such as, for example, superalloys, wear-resistant steels and nickel alloys of any shape, size and heat treatment.

Still advantageously, the inclination of the cutting tips, obtained by grinding them, allows configurations to be made such as to obtain a cutting groove, or cutting channel, which limits the friction of the tool with the materials.

In addition, still advantageously, the different inclinations of the cutting tips, which are obtained by grinding these latter, allow a fine division of the chip in the cutting channel to be achieved, obtaining many more chips than normal hard metal set blades.

Unlike the equivalent tools present in the prior art, the setting of the teeth of the tool of the invention is not carried out by bending, but by asymmetric grinding of the tips. This means that the support bases of the teeth are substantially straight.

Therefore, advantageously, the teeth are characterized by a greater mechanical strength than that of the known equivalent devices, since the grinding of the tips does not involve the yielding of the teeth themselves.

Still advantageously, a substantially rectilinear arrangement of the support bases, i.e. comprised in a plane longitudinal to the support body, allows the teeth to be loaded with greater stresses than the equivalent known devices without subjecting the teeth of the tool to torsion.

Still advantageously, the welding plane of the hard metal cutting tip is orthogonal to the feed direction, as well as each cutting edge on the asymmetric ground teeth that in this way will not give rise to lateral components of the cutting forces.

Still advantageously, the conformation of the support bases allows better distribution of the stresses sustained with respect to the equivalent tools present in the prior art.

In other words, the tool of the invention enables the realization of cutting substantially similar to that of the devices present in the known art but, advantageously, allows the tool itself to be loaded with greater stresses, since the cutting groove is realized by shaping the flanks of the cutting tips and not by bending the support bases of the teeth.

Moreover, still advantageously, the tool of the invention allows each type of band saw to be able to apply a greater thrust to the arc obtaining a greater number of precise cuts.

Still advantageously, the above allows the obtaining of a greater number of cuts made in a shorter time than the known hard metal set blades.

Still advantageously, the above allows the feed speed of the tool to be increased while decreasing the noise and vibrations sustained by the teeth.

On closer inspection, therefore, still advantageously, the cutting tool of the invention, with the same speed, is able to work for a greater number of hours than the equivalent devices present in the known art.

From what has been said so far, it is evident that the purposes disclosed are also achieved by a method of executing a cutting tool.

In particular, it comprises at least the following steps: providing a plurality of teeth comprising at least a support base emerging from at least a substantially laminar support body, the support base being substantially comprised in a plane longitudinal to the support body; stably coupling multiple cutting elements to the support bases; laterally grinding at least a subset of the cutting elements to shape the inclination and/or conicity of at least one flank thereof so as to make at least one asymmetric cutting tip, typically but not necessarily at least one pair of cutting tips, having a flank inclined with respect to the aforementioned longitudinal plane to widen the cutting groove.

Brief description of the drawings

Further features and advantages of the invention will become more evident in light of the detailed disclosure of a preferred but non-exclusive embodiment of a cutting tool according to the invention, illustrated by way of non-limiting example with the aid of the accompanying drawings, wherein:

Fig. 1 shows the cutting tool of the invention in a schematic lateral view;

Fig. 2 shows a schematic front view of the tool in Fig. 1 ;

Fig. 3 shows a schematic top view of the tool in Fig. 1 ;

Figs. 4 and 5 show an embodiment of the invention in a schematic side view and front view;

Fig. 6 shows a particular schematic of the teeth of the embodiment of Figs. 4 and 5;

Figs. 7 and 8 show an embodiment of the invention in a schematic front and top view;

Fig. 9 shows a particular schematic of the teeth of the embodiment of Figs. 7 and 8;

Figs. 10 and 11 show an embodiment of the invention in a schematic side view and front view;

Fig. 12 shows a particular schematic of the teeth of the embodiment of Figs. 10 and 11.

Detailed disclosure of an exemplary preferred embodiment

With reference to the Figures mentioned, in particular to Figure 1 , a cutting tool 1 is described, particularly suitable for use in band saws and circular saws, according to the invention.

In particular, it comprises a substantially laminar support body 3 and a plurality of cutting teeth 6.

According to one aspect of the invention, the cutting teeth 6 are provided with a support base 7 emerging from the support body 3 and a cutting tip 9 generally made of hard metal such as, for example, carbide.

Advantageously, the cutting tip 9 allows the tool 1 of the invention to cut even the most resistant materials such as superalloys and wear-resistant steels.

Said cutting tips 9 are stably coupled to respective support bases 7 typically, but not necessarily, by electro-welding.

According to another aspect of the invention, the teeth 6 comprise a subset of asymmetric teeth 12 in which the support base 7 is substantially comprised in a plane longitudinal to the support body 3, not shown in the Figures.

In other words, despite the asymmetry, in such teeth 12 the support base 7 is substantially straight, i.e. it does not deviate from the support body 3.

According to a further aspect of the invention, in the asymmetric teeth 12 the cutting tip 9 is ground laterally to shape the inclination and/or the conicity of one flank 14. Typically, but not necessarily, the grinding is performed on one or more pairs of finishing teeth, i.e. the outer teeth.

According to the embodiment of the invention described herein, the flank 14 is uniformly shaped. Obviously, this should not be considered limiting for different forms of the invention where, for example, a flank comprises several faces with different shaping and conicity.

Furthermore, again according to the embodiment of the invention that is described, the opposite flank 15 to the inclined flank 14 is ground according to any inclination and/or conicity, regardless of what is performed on the flank 14.

According to another aspect of the invention, the grinding of the flank 14 is made to set the cutting tip 9 by inclining the flank 14 with respect to the plane longitudinal to the support body 3, as can be seen in Figures 2 and 3. Consequently, the tool 1 of the invention will have a cutting groove, or channel, wider than the thickness of the support body 3 and shaped according to predetermined inclinations and conicity. As mentioned, unlike the equivalent tools present in the prior art, the tool 1 of the invention is set by shaping the flank 14 of the cutting tip 9 and this advantageously improves the accuracy of the setting compared to the known tools where the bending limits the precision and repeatability of the execution.

Still advantageously, the grinding allows the flanks 14 to be shaped according to any inclination allowing, still advantageously, any configuration of the cutting groove of the tool 1 to be realized.

Moreover, the shaping of the cutting tips 9, carried out by grinding, allows the cutting channel to be modified by acting on the inclination and/or the conicity of the tips 9 without having to bevel them. In other words, the precision and accuracy of the grinding allows, still advantageously, any bevelling of the tips to be eliminated with the consequent advantages of force distribution. In fact, the bevels typical of known equivalent blades generate the formation of transverse stresses that can cause damage.

Still advantageously, the cutting tool 1 of the invention has the support base 7 of the asymmetric teeth 12 substantially straight so as to allow the tool 1 itself to more effectively absorb the stresses compared to the known equivalent devices.

Moreover, by grinding, the teeth 12 of the invention do not undergo a yielding due to bending.

In other words, given the geometry of the support bases 7, the tool 1 of the invention is still advantageously suitable for sustaining greater stresses than the equivalent tools present in the known art, without incurring torsion or other damages that would compromise its functionality.

In the prior art, the small torsion angles of the tooth set during the cutting process undergo a flexion towards the body eliminating their effectiveness. However, still advantageously, the geometry of the teeth 6 of the invention eliminates, or at least limits, this drawback.

Thus, the asymmetric geometry of the cutting tips 9 still advantageously improves the response to cutting stresses by optimising the setting process.

Moreover, the cutting tool 1 , again with respect to the known equivalent devices, allows, with the same cutting, proceeding with a greater feed speed and, at the same time, allows the noise and vibrations during use to be limited. Furthermore, still advantageously, the tool 1 of the invention once the cutting has been carried out and therefore when it is returning upwards, does not require the spacing of the divided parts as it behaves like the hard metal set blades present in the known art. In fact, the symmetrical teeth have a thickness substantially equal to the support body 3 and the asymmetrical teeth 12, i.e. the external finishing teeth, have a greater thickness than the support body 3 only on one side, in particular on the side of the flank 14, so as to avoid, or at least limit, pinching and snapping on both sides.

Advantageously, therefore, the cutting tool 1 of the invention, by grinding the cutting tips 9, allows asymmetric teeth 12 to be obtained, capable of absorbing greater stresses than the known equivalent devices and which make a groove such as to limit friction.

The cutting tool 1 of the invention is more powerful than the equivalent blades present in the prior art and, thanks to the advantages disclosed thus far, is also more durable since the stresses sustained, as mentioned, are limited by the geometric characteristics obtained by grinding the cutting tips 9.

On closer inspection, therefore, with respect to the equivalent tools present in the known art, the cutting tool 1 of the invention does not provide for the bending of the teeth 6, has teeth 6 with different thicknesses, allows the cutting tips 9 to be shaped according to different conicity and angles even in the same tooth and, finally, features an asymmetry of the pairs of the asymmetric teeth 12, in particular of the finishing teeth that remove the material between the tool 1 itself and the cut surface.

According to a further aspect of the invention, the grinding of the cutting tips 9 is also conducted along the back 16 and/or the front part 17.

Advantageously, this makes it possible to simplify the execution of the tip 9 according to the predetermined shapes, consequently improving the cutting efficiency.

Furthermore, still advantageously, similarly to the abovementioned, the shaping of the back 16 and of the front part 17 of the cutting tip 9 allows a geometric shape to be obtained that adapts to the inclinations of the support base 7.

According to the aforementioned, the tool 1 of the invention allows any shape of the flanks 14 to be made, adhering precisely the predetermined configuration.

The cutting tool 1 may be characterized by a group of different tooth lengths (pitch) that are repeated along the extent of the tool 1 (length).

In particular, by way of non-limiting example for different embodiments of the invention, any group of pitches is possible. Furthermore, the configuration of the tool 1 can have an order of some teeth 9 that differs from the number of teeth typical for the pitch, thus realizing a variable pitch configuration.

For example, according to the embodiment of the invention shown in Figures 4 to 6, the cutting tool 101 comprises a sequence of 6 teeth 106 having their respective cutting tips 109 ground according to different inclinations and/or conicity.

According to another embodiment of the invention shown in Figures 7 to 9, the cutting tool 201 comprises a sequence of 9 teeth 206 having their respective cutting tips 209 ground according to different inclinations and/or conicity.

This configuration allows a sequence, or pitch, to be obtained with 3 pairs of set teeth. Advantageously, the sequence of 9 teeth 206 allows the distribution of the loads to be improved so that there is less vertical cutting force on large sections.

Also, by way of non-limiting example for different embodiments of the invention, according to a further embodiment variant of the invention shown in Figures 10 to 12, the cutting tool 301 comprises a sequence of 5 teeth 306 of which only 2 comprise an asymmetric cutting tip 309.

Operationally, for the execution of a cutting tool 1 such as the one disclosed thus far, the method is as follows.

First, a substantially laminar support body 3 is provided, from which a plurality of support bases 7 of respective teeth 6 emerge. In particular, said support bases 7 are substantially comprised in a plane longitudinal to the support body 3 itself.

Subsequently, cutting elements, typically but not necessarily cylindrical inserts, are coupled to the support bases 7.

Then, at least a subset of the cutting elements, typically but not necessarily the finishing teeth (i.e. the external teeth), is laterally ground to shape the inclination and/or the conicity of a flank 14 of said at least one portion of said more cutting elements so as to make a cutting tip 9 of an asymmetric tooth 12 having the flank 14 inclined with respect to said longitudinal plane to widen the cutting groove.

In addition, according to the embodiment of the invention that is described, the execution of the cutting tool 1 also provides for the grinding of the front part 17 and/or the back 16 of the cutting elements.

Advantageously, the method of execution allows the realization of a cutting tool 1 according to what has been disclosed above. In fact, the method involves implementing the setting of the teeth 12 by grinding the cutting tips 9.

The summary of the advantages of a cutting tool 1 made according to the method described is omitted here, as it would be a repetition of what is disclosed above during the disclosure of the tool 1 of the invention. What is observed is that it achieves all the aforementioned advantages.

In light of the foregoing, it is therefore understood that the cutting tool of the invention achieves all the intended objects.

In particular, it also allows cutting of special materials and has a cutting groove capable of limiting friction.

Moreover, from the geometry and the setting obtained by grinding the cutting tips, it is able to withstand greater stresses and, consequently, to advance with a greater cutting speed than the equivalent devices present in the known art.

Moreover, the tool of the invention produces less noise and vibrations than the known equivalent tools.

On closer inspection, therefore, the cutting tool of the invention is more powerful than the known equivalent devices and, in addition thereto, is also more durable.

The invention is subject to numerous modifications and variations, all falling within the appended claims. All details and phases may be replaced by other technically equivalent elements, and the materials may be different as required, without departing from the scope of protection of the invention defined by the attached claims.