WO2011033541A1

WO2011033541A1 - Multi-wire machine for cutting stone material

Info

Publication number: WO2011033541A1
Application number: PCT/IT2009/000428
Authority: WO
Inventors: Marco Terzo Pellegrini
Original assignee: Pelmine S.R.L.
Priority date: 2009-09-21
Filing date: 2009-09-21
Publication date: 2011-03-24

Abstract

A multi-wire machine (1) for cutting stone material (2) comprises a base structure (3) which can rest on the ground (4) and a supporting frame (5) comprising a base portion (6) and slidably mounted on the base structure (3). The multi-wire machine (1) also comprises a plurality of cutting devices (11) mounted parallel with each other on the supporting frame (5); each cutting device (11) in turn comprising: at least a first motor- driven flywheel (12) and a second flywheel (13) which are coplanar, spaced out, each having its own axis of rotation (14) and rotating relative to the supporting frame (5); at least one cutting wire (15) wound, along a looped path, at least around the flywheels. Moreover, along the cutting wire (15) path, in practice, there is an active stretch (16), for cutting the stone material (2), and a return stretch (17); moreover, the first flywheels (12) are mounted on first supporting means (19) and the second flywheels (13) are mounted on second supporting means (20), both supporting means (19, 20) extending between two opposite ends (24, 25). The machine (1 ) also comprises an operating space (21 ) extending parallel with the supporting means (19, 20) for the flywheels (12, 13) and laterally limited by the set of active stretches (16), by the set of return stretches (17) and by the first and second flywheels. The supporting frame (5) comprises an extension portion (22) extending cantilever-style from the base portion (6), passing through the operating space (21), towards a front part (23) of the machine (1); moreover, each of the flywheel supporting means (19, 20) has both ends (24, 25) mounted on the supporting frame (5), at least one on the extension portion (22).

Description

MULTI-WIRE MACHINE FOR CUTTING STONE MATERIAL

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DESCRIPTION

This invention relates to a multi-wire machine for cutting stone material, designed to obtain a plurality of slabs from blocks of materials such as marble, granite, etc.

The scope of this invention in general covers all types of machines for cutting blocks of stone material which use more than one wire. In general, multi-wire machines for cutting stone material comprise: a base structure resting on the ground, a supporting frame slidably mounted (so that it can move vertically) on the base structure, a plurality of cutting devices mounted parallel with each other on the supporting frame. Each of these cutting devices comprises: at least a first and a second flywheel which are coplanar, spaced out and rotatably mounted on the supporting frame, and a cutting wire wound around at least the flywheels.

In general, in each cutting device, at least one motor is connected to at least one of the first flywheels and in practice makes the flywheel rotate, thus moving the cutting wire. Each wire is of the type impregnated with diamond, that is to say, wires with a metal core which are normally coated with a resin containing diamond fragments. The cutting wire mounted on the machine usually identifies a path comprising an outward stretch (where the wire cuts) and a return stretch (this is normally the stretch of path highest above the ground).

Each cutting device also has a tensioning system which guarantees tensioning of the individual cutting wire during the entire cutting operation. In practice the supporting frame slides on the fixed structure in a vertical direction so that when it is in the highest position relative to the ground a block of stone material is positioned below it. Then the supporting frame is lowered, after activating the motor which starts the flywheels. In this way, the block of stone material is cut to produce a plurality of slabs.

In particular, the supporting frame mainly extends between two ends which slide on the base structure. The latter is usually formed by two vertical columns connected by a crosspiece at the top. The flywheels are usually rotatably mounted on the supporting frame by means of their own supporting shafts (extending between two ends) and are spaced out at least horizontally. These flywheels rotate about their own axis perpendicular to the main extension of the supporting frame. The supporting shafts can be mounted on the supporting frame each at one end or both, but in the most common embodiments they are each connected to the frame at only one end.

Operating requirements mean that the number of cutting devices mounted on the supporting frame for cutting the block is increasingly greater. Therefore, there is an increase in the number of flywheels, the number of cutting wires, etc. This brings a significant increase in the weight on the supporting frame which supports the cutting devices. In particular, the supporting shafts of the first and second flywheels must be mounted on the frame at both of their ends. Therefore, a supporting frame is needed which extends both along a front part of the machine, and along a rear part of the machine (the front and rear parts are the parts through which the block of marble can access the machine). For example, the base structure may be formed by four columns so as to be able to support the supporting frame both at the front and the rear. However, this known technology has several disadvantages. In particular, the main problem is that the supporting frame, shaped in that way, obstructs access to the machine cutting wires, for example when they must be substituted. Each cutting wire is wound (in practice) in a looped path, around the flywheels and therefore (depending on requirements) there must be the possibility of taking it off or placing it around the flywheels.

In some alternative embodiments of this second technology there are devices present which allow partial detachment of the flywheel shafts from the supporting frame to allow access to the cutting wires. Obviously, this type of prior art embodiment is complex and requires a significant amount of time and money. The detaching devices are expensive and, in order to gain access to the cutting wires, an operation to detach the flywheel supporting shafts from the frame must be carried out.

In this situation, the technical purpose which forms the basis of this invention is to provide a multi-wire machine for cutting stone material which overcomes the above-mentioned disadvantages.

In particular, the technical purpose of this invention is to provide a multi- wire machine for cutting stone material which allows a large number of cutting devices to be present, at the same time guaranteeing easy access to the cutting wires (for changing the wires when necessary).

The technical purpose specified and the aims indicated are substantially achieved by a multi-wire machine for cutting stone material as described in the appended claims.

Further features and the advantages of this invention are more apparent in the detailed description below, with reference to a preferred, non- limiting embodiment of a multi-wire machine for cutting stone material, illustrated in the accompanying drawings, in which:

- Figure 1 is an axonometric view of the multi-wire machine for cutting stone material made in accordance with this invention, with the cutting wires removed for clarity;

- Figure 2 is a front view of the multi-wire machine for cutting stone material of Figure 1 ;

- Figure 3 is a side view of the multi-wire machine for cutting stone material of Figure 1 ;

- Figure 4 is a top view of the multi-wire machine for cutting stone material of Figure 1 ;

- Figure 5 is a cross-section according to the line V - V of the multi- wire machine for cutting stone material of Figure 4;

- Figure 6 is a cross-section according to the line VI - VI of the multi- wire machine for cutting stone material of Figure 2;

- Figure 7 is a view of the multi-wire machine for cutting stone material of Figure 2 in a home position, also showing the cutting wires.

With reference to the accompanying drawings, the numeral 1 denotes as a whole a multi-wire machine for cutting stone material 2 in accordance with this invention.

The multi-wire machine 1 for cutting stone material 2 comprises a base structure 3 resting on the ground 4 and a supporting frame 5 having a base portion 6 mainly extending horizontally between two opposite ends 7. The supporting frame 5 is slidably mounted (in such a way that it can move vertically) on the base structure 3 at the ends 7 of the base portion 6. In this way the supporting frame 5 can move vertically between a home position 8 (in which it is raised relative to the ground 4 allowing insertion and extraction of the block of stone material 2) and an end of cut position 9 (in which it is lowered after cutting the block of stone material 2). In the preferred embodiment, the base portion 6 is mainly positioned at a rear part 10 of the machine 1.

Mounted on the supporting frame 5 there is a plurality of cutting devices 11 (mounted parallel with each other). Each cutting device 11 in turn comprises at least a first motor-driven flywheel 12 and a second flywheel 13, spaced out horizontally and each having its own axis of rotation 14. The first flywheel 12 and the second flywheel 13 are rotatably mounted on the supporting frame 5 in such a way that they can rotate about their axis of rotation 14. Moreover, each cutting device 11 forms a vertical plane passing through the respective cutting wire 15 and through the two flywheels 12, 13 (which are therefore coplanar).

Each cutting device 11 also comprises at least one cutting wire 15 wound, along a looped path, at least around the first flywheel 12 and the second flywheel 13. Along the path of the cutting wire 15 there is an active stretch 16, for cutting the stone material 2, and a return stretch 17. The first and second flywheels 12 and 13 (relating to a cutting device 11), having the same wire 15 wound around them along a looped path, are positioned in such a way that they are in the same vertical plane passing through the flywheels 12, 13.

In the embodiment illustrated in Figure 7 the active stretch 16 and the return stretch 17 of the cutting wire 15 path are also shown. The active stretch 16 is the lower one (relative to the ground 4) and the return stretch 17 is the higher one (again relative to the ground 4). The cutting device 11 also comprises tensioning means 18 connected at least to the second flywheel 13, which are operatively active at least on the latter for adjusting the tension of each cutting wire 15.

The first flywheels 12 are mounted on first supporting means 19 (for example, a shaft) and the second flywheels are also mounted on second supporting means 20 (for example, a shaft). Both supporting means 19, 20 extend, between two opposite ends 24, 25, from the base portion 6 of the supporting shaft 5 (horizontally and substantially perpendicular to its main direction of extension) towards a front part 23 of the machine 1. There is also an operating space 21 extending parallel with the supporting means 19, 20 and which is laterally limited by the set of active stretches 16, by the set of return stretches 17 and by the first and second flywheels 12, 13.

According to this invention, the machine 1 supporting frame 5 also comprises an extension portion 22 extending cantilever-style from the base portion 6, passing through the operating space 21 , towards the front part 23 of the machine 1. Moreover, both of the flywheel supporting means 19, 20 have both ends 24, 25 mounted on the supporting frame 5, at least one on the extension portion 22 at the front part 23 of the machine 1.

In the preferred embodiment illustrated in Figure 1 the extension portion 22 comprises at least two arms 26 extending, each close to the flywheels 12, 13, between an end 27, to which the end 24 of the supporting means 19, 20 for the first and second flywheels 12, 13 is connected, corresponding to the front of the front part 23 of the machine 1 , and an end 28 which is rigidly connected to the base portion 6 of the supporting frame 5.

In particular, in the preferred embodiment the arms 26 comprise several parts: one or more first parts 29 parallel with the supporting means 19, 20 for the flywheels 12, 13 and rigidly connected to the base portion 6 of the supporting frame 5 (corresponding to the end 28 of the arms 26 connected to the base portion 6 of the supporting frame 5), and a second part 30 continuing on from the first parts 29 and extending perpendicularly to them, on which an end 24 of the supporting means 19, 20 for the first and second flywheels 12, 13 is mounted. Figure 1 shows how the second part 30 of the arm 26 closest to the first flywheels 12 is preferably a triangular structure 31 , having the shape of a right-angled triangle (more clearly visible from the front in Figure 2), in which the shortest leg 32 (horizontal) is a crossbar 33 on the end of which the supporting means 19 for the first flywheels 12 are mounted, whilst the longest leg 34 (vertical) connects the crossbar 33 to the first parts 29 of the arm 26 (Figure 1). Advantageously, the hypotenuse 35 of this triangular structure 31 connects the two legs 32, 34 making the second part 30 of the arm 26 stronger.

In contrast, the second part 30 of the arm 26 closest to the second flywheels 13 comprises two supporting elements 36, 37 which are perpendicular to each other (one horizontal 36 and one vertical 37) and an angular structure 38 (visible in Figure 2) which connects them and makes the arm 26 strong. The vertical supporting element 37 corresponds to the longest leg 34 of the second part 30 of the arm 26 closest to the first flywheels 12, whilst the angular structure 38 forms the part of the supporting frame 5 on which the second supporting means 20 for the second flywheels 12 are mounted.

The arms 26 are advantageously rigidly connected to each other by a first crosspiece 39 extending transversally to the supporting means 19, 20 for the flywheels 12, 13 and close to the return stretch 17 of the path of the cutting wire 15 closest to the front part 23 of the machine 1.

In the preferred embodiment illustrated in Figure 2, the situation shown is one in which a block of stone material 2 is positioned below the machine 1 when the supporting frame 5 is in the end of cut position 9. Figure 2 shows the slab stop supports 40 which support the slabs after cutting (these are well known in the sector) and which are mounted on the carriage 41 which carries the block of stone material 2. The first crosspiece 39 is therefore advantageously located above the maximum height of the slab stop supports 40 usable. In this way, the supporting frame 5 moving down from the home position 8 towards the block of stone material 2 (for cutting) does not interfere in any way with the slab stop supports 40.

In particular, again in Figure 2, it can be seen how the first crosspiece 39 is rigidly connected between the vertical leg 34 and the vertical supporting element 37 in such a way as to form a right angle with them. In this angle there may advantageously be additional angular supports 42 (visible in Figure 2) giving the extension portion 22 of the supporting frame 5 (and in particular the first crosspiece 39) greater stability and strength.

The machine 1 base structure 3 comprises two vertical columns 43 on which the supporting frame 5 (as already indicated) is slidably mounted. Each vertical column 43 has a lower end 44 resting on the ground 4 and an upper 45. The lower ends 44 of the vertical columns 43 may be secured directly to the ground 4 (even using supporting blocks 85 as in Figure 1) or may be mounted on a mobile carriage. The upper ends 45 of the vertical columns 43 are connected to each other by a second crosspiece 46 perpendicular to the columns 43 and parallel with the ground 4. The second crosspiece 46, in the embodiment illustrated in Figure 1 , preferably comprises two parts 47 rigidly connected to each other at a connecting point 48 at about the machine 1 halfway point seen from the front (Figure 2).

In the preferred embodiment (Figure 1) each vertical column 43 is substantially a parallelepiped with four lateral walls: the first 49 facing towards the flywheels; the second 50 parallel with and opposite the first 49 (facing towards the outside), the third 51 facing towards the front part 23 and the fourth 52 facing towards the rear part 10 of the machine 1. The third wall 51 and the fourth wall 52 (for one of the two columns 43) and only the fourth wall 52 (for the other column) preferably have a sliding track 53 extending at least along the entire stroke of the supporting frame 5. Moreover, rotatably mounted close to the second lateral wall 50 of each vertical column 43 there is a threaded bar 54 (shown more clearly in Figure 3) which runs parallel with the column 43 between the ground 4 and the upper end 45 of the column 43. As shown in Figure 5, mounted cantilever-style at the upper end 45 of one of the two columns 43 there is a supporting structure 55 for a motor 56 which makes the threaded bar 54 rotate (using a suitable reduction unit 57). Also in the preferred embodiment in Figure 5 the motor 56 is preferably mounted on the right- hand vertical column 43, but the movement is also transmitted to the left- hand vertical column 43 by a suitable drive shaft 58 running inside the second crosspiece 46 to the upper end 45 of the left-hand vertical column 43 where it is connected to the respective threaded bar 54, for moving it in such a way that it is synchronised with the other bar.

Each end 7 of the base portion 6 of the supporting frame 5 preferably comprises coupling means 59 for slidably mounting the supporting frame 5 on the base structure 3. For each column 43, these coupling means 59 comprise at least one internally threaded bushing 60 screwed onto the threaded bar 54 for transforming the rotating motion of the threaded bar 54 into a vertical motion by the supporting frame 5. In this way the supporting frame 5 can move vertically. Figure 3 shows how each end 7 of the base portion 6 of the supporting frame 5 is formed by a slide 61. In the preferred embodiment illustrated in the accompanying drawings, one of the two slides 61 (the one on the right in the drawings) surrounds each vertical column 43 at the second wall 50, the third wall 51 and the fourth wall 52, whilst the other slide 61 (the one on the left in the drawings) surrounds only the second wall 50 and the fourth wall 52. Therefore, one slide 61 can slide along the third wall 51 and the fourth wall 52 of the respective vertical column 43, whilst the other slide 61 can slide along the second wall 50 and the fourth wall 52 of the respective vertical column 43 (at the sliding tracks 53), whilst each slide 61 is connected to the bar 54 by the threaded bushing 60.

Moreover, in a preferred embodiment, the machine 1 as a whole is advantageously made in such a way that the centre of gravity of the supporting frame 5 (including the cutting devices 11 and everything mounted on it) falls in a vertical plane passing through the coupling means 59. In this way, the coupling means 59, and consequently the columns 43, are only subjected to a vertical compression action and no moments are generated at them. Therefore, no moments of force are generated at the bars 54. In the embodiment illustrated the vertical plane will be that passing through the threaded bushings 60 screwed onto the threaded bars 54.

In alternative embodiments, not illustrated, the slide 61 may slide along the first wall 49 and the second wall 50, or only along one of the four walls, and the bar may be positioned at the first wall 49, the third wall 51 or the fourth wall 52. What is important is that the centre of gravity falls in the vertical plane passing through the coupling means 59.

The multi-wire machine 1 for cutting stone material 2 also comprises, for each cutting device 11 , at least one idle auxiliary flywheel 62 rotatably mounted on the supporting frame 5 close to the main second flywheel 13 and at least vertically distanced from it. The auxiliary flywheels 62 also have their own auxiliary supporting means 63 (for example a shaft, like the other flywheels) and each auxiliary flywheel 62, together with the other flywheels 12, 13, forms the sliding path on which one of the cutting wires 15 is wound. In the embodiment illustrated in Figure 5 it can be seen how the auxiliary supporting means 63 are preferably mounted on a supporting bracket 64 in turn rotatably connected (at its first end 65) to the supporting frame 5 at the horizontal supporting element 36 of the second part 30 of the arm 26 close to the second flywheel 13. In this way, the auxiliary flywheels, mounted on the respective auxiliary supporting means 62, can rotate relative to the supporting frame 5 and at the same time can move their axis of rotation thanks to the movement of the supporting bracket 64 relative to the supporting frame 5.

The multi-wire machine 1 also comprises (as already indicated) tensioning means 18 which are divided into rough tensioning means 66 (in the embodiment illustrated these are positioned close to the auxiliary flywheel 62) and precision tensioning means 67 (connected to the second flywheels). The rough tensioning means 66 comprise at least one actuator 68 connected between the supporting frame 5 and the auxiliary supporting means 63. In particular, in the accompanying drawings the actuator 68 is connected to the supporting bracket 64 (on which the auxiliary supporting means 63 are mounted). In the preferred embodiment illustrated in the accompanying drawings, the actuator 68 comprises a threaded rod 69 (to which a second rod 70 for supporting end of stroke sensors is connected) extending from the supporting frame 5 (at the horizontal supporting element 36 of the second part 30 of the arm 26 close to the second flywheel 13) towards the auxiliary supporting means 63. The threaded rod 69 close to the supporting frame 5 is mounted (at its first end 71) on a connecting element 72 in turn rotatably mounted on the supporting frame 5. Moreover, the threaded rod 69 is rotatably mounted (in such a way that it can rotate about its own axis) on the connecting element 72. Screwed onto the threaded rod 69 there is a female screw 73 rotatably connected to the supporting bracket 64 (it is the part of the actuator 68 connected to the supporting bracket 64). There are also motor-driven means connected to the threaded rod 69 to make it rotate about its axis and to move the female screw 73 along the threaded rod 69 so as to move the auxiliary supporting means 63 between a minimum tensioning position and a maximum tensioning position.

The auxiliary flywheels 62 may have any structure suitable for the purpose. In particular, they may be made as described in patent EP 1 598 162, that is to say, with an idle drum to which only one auxiliary flywheel 62 is fixed, whilst the others are mounted in such a way that they are idle on the drum. In this way, the drum rotates at the speed imparted to it by the auxiliary flywheel fixed to it, whilst the differences in speed with the other auxiliary flywheels 62 are compensated for by their relative rotation relative to the drum.

Therefore, at the moment of mounting the cutting wire 15 the auxiliary flywheel 62 will be in the minimum tensioning position. Then, when the wires are mounted on the machine 1 , a command will be issued to the actuator 68 to move the auxiliary flywheel 62 towards the maximum tensioning position. Therefore, when the auxiliary flywheel 62 is in the minimum tensioning position, the cutting wires 15 can be accessed from the front part 23 of the machine 1 to remove or insert them.

The precision tensioning means 67 advantageously comprise a plurality of operating units 74, each connected to a second flywheel 13 and able to translate the respective axis of rotation 14 so that in practice the cutting wire 15 is kept taut independently of the others. In particular, in the preferred embodiment illustrated in the accompanying drawings, the operating units 74 are each inserted in a housing located at the centre of the second flywheel 13. Depending on requirements, the tensioning means 67 may have any configuration, for example, those described in patent EP 1024314 and in Italian patent applications TO2005A000669 and VI2007A000150.

In the preferred embodiment illustrated in the accompanying drawings, the first flywheels 12 of each cutting device 11 (unlike the second flywheels) are formed by two motor-driven drums 75 positioned side by side. However, in general, there may be one or more drums.

Moreover, there is a plurality of guide rollers 76 rotatably mounted on the supporting frame 5 and forming, together with the flywheels, the looped path on which the cutting wires 15 are wound. In the preferred embodiment illustrated in Figure 5 the guide rollers 76 are advantageously mounted on the supporting frame 5 at the lowest part (relative to the ground 4) of the second parts 30 of the arms 26.

The machine 1 also comprises a plurality of ducts 77 for conveying water (for cooling and cleaning) mounted on the supporting frame 5 close to the first crosspiece 39 and extending from it towards the base portion 6 of the supporting frame 5. These ducts 77 have a plurality of holes 78 along their length for letting out water for cooling the cutting devices 11 during use. Each duct has its own tap 79 close to the first crosspiece 39 (and therefore the front part 23 of the machine 1) for connecting external ducts supplying the water. During machine 1 operation, the water flows in the ducts 77 and comes out of the holes 78 creating a rain effect on the block of stone material 2, wetting the dusts and cooling the cutting wires 15. The machine 1 according to this invention comprises at least two protective guards 80 connected to the supporting frame 5, each close to the first and second flywheels 12, 13. Each guard 80 comprises a main surface 81 extending vertically and which at its highest point bends towards the flywheels closest to it. There is also a vertical lateral surface 82, connected to the main surface 81 , delimiting the guard 80 at the front part 23 of the machine 1. The protective guards 80 protect the columns 43 (with the above-mentioned vertical movement mechanisms such as the slide 61 , sliding tracks 53, etc.) from dust from the stone material 2 and from splashes of water produced during cutting of a block of material 2. There are also other protective elements 83 for the motor 56 for the supporting frame 5 vertical movement and for the reduction units 57 positioned on the upper ends 45 of the vertical columns 43 (shown in Figure 2 but cut away in Figure 4).

Moreover, there is preferably a control and adjustment unit present (not illustrated in the accompanying drawings) which allows manual or automatic control of the machine 1 as a whole.

Use of the multi-wire machine 1 for cutting stone material 2 is immediately derived from what is described above. In general, operation of the multi- wire machine 1 for cutting stone material is already known and is not described herein. The part of greatest relevance in this text is access to the cutting wires 15. When access to the wires 15 is needed, the operator can act on the rough tensioning means 66 which, by means of the actuator 68, move the auxiliary flywheels 62 to the minimum tensioning position. In this way, since the machine 1 can be accessed from the front (thanks to the structure of the supporting frame 5), the cutting wires 15 can easily be changed, since each wire 15 is longer than the looped path formed by the relative flywheels. In this way, the wire 15 can be lifted over the first crosspiece 39 towards the front part 23 of the machine 1 without being obstructed by the supporting frame 5, thus removing the wires from the front part 23 of the machine 1.

After removing one or more cutting wires 15 from the machine 1 , one or more wires can be inserted on it (according to requirements) by performing the removal operation in reverse. Finally, a command is issued to the actuator 68 to move towards the maximum tensioning position.

This invention brings important advantages.

First, the machine comprises a plurality of cutting devices related to the operating requirements in the sector. At the same time the machine has a supporting frame structured in such a way that it allows easier access (frontal) to the cutting wires, for example for substituting them (if necessary).

It should also be noticed that this invention is relatively easy to produce and even the cost linked to implementation of the invention is not very high.

The invention described above may be modified and adapted in several ways without thereby departing from the scope of the inventive concept. All details of the invention may be substituted by other technically equivalent elements and, in practice, all of the materials used, as well as the shapes and dimensions of the various components, may vary according to requirements.

Claims

1. A multi-wire machine (1) for cutting stone material (2), comprising:

- a base structure (3) which can rest on the ground (4);

- a supporting frame (5) comprising a base portion (6) extending mainly horizontally between two ends (7), and slidably mounted on the base structure (3) at the ends (7) of the base portion (6); the base portion (6) being mainly positioned at a rear part (10) of the machine (1);

- a plurality of cutting devices (11) mounted parallel with each other on the supporting frame (5); each cutting device (11) in turn comprising:

at least a first motor-driven flywheel (12) and a second flywheel (13) which are coplanar, spaced out, each having its own axis of rotation (14) and rotating relative to the supporting frame (5); at least one cutting wire (15) wound, along a looped path, at least around the flywheels; in practice, along the cutting wire (15) path there being an active stretch (16), for cutting the stone material (2), and a return stretch (17);

tensioning means (18) connected at least to the second flywheel (13) and operatively active at least on the latter for adjusting the tension of each cutting wire (15);

the first flywheels (12) being mounted on first supporting means (19) and the second flywheels (13) being mounted on second supporting means (20), both of the supporting means (19, 20) extending between two opposite ends 24, 25); an operating space (21) extending parallel with the supporting means (19, 20) and being laterally limited by the set of active stretches (16), by the set of return stretches (17) and by the first and second flywheels;

the machine being characterised in that the supporting frame (5) comprises an extension portion (22) extending cantilever-style from the base portion (6), passing through the operating space (21), towards a front part (23) of the machine (1); and also being characterised in that each of the flywheel supporting means (19, 20) has both ends (24, 25) mounted on the supporting frame (5), at least one on the extension portion (22) at the front part (23) of the machine (1).

2. The multi-wire machine (1) for cutting stone material (2) according to claim 1 , characterised in that the extension portion (22) comprises at least two arms (26) each extending close to the first and second flywheels; each of the arms (26) having an end (27) to which the end (24) of the supporting means (19, 20) for the first and second flywheels is connected at the front part (23) of the machine (1).

3. The multi-wire machine (1) for cutting stone material (2) according to claim 2, characterised in that the extension portion (22) comprises a first crosspiece (39) which rigidly connects the arms (26) to each other and which extends transversally to the supporting means (19, 20) for the flywheels and close to the return stretch (17) of the path of the cutting wire (15) closest to the front part (23) of the machine (1).

4. The multi-wire machine (1) for cutting stone material (2) according to any of the foregoing claims, characterised in that the base structure (3) comprises two vertical columns (43) on which the supporting frame (5) is slidably mounted; each vertical column (43) having a lower end (44) which rests on the ground (4) and an upper end (45); the upper ends (45) being connected by a second crosspiece (46).

The multi-wire machine (1) for cutting stone material (2) according to any of the foregoing claims, characterised in that each end (7) of the base portion (6) of the supporting frame (5) comprises coupling means (59) for slidably mounting the supporting frame (5) on the base structure (3).

The multi-wire machine (1) for cutting stone material (2) according to claim 5, characterised in that the centre of gravity of the supporting frame (5) falls in a vertical plane passing through the coupling means (59).

The multi-wire machine (1) for cutting stone material (2) according to any of the foregoing claims, characterised in that the tensioning means (18) comprise rough tensioning means (66) and precision tensioning means (67).

The multi-wire machine (1) for cutting stone material (2) according to any of the foregoing claims, characterised in that each cutting device (11) comprises at least one idle auxiliary flywheel (62) rotatably mounted on the supporting frame (5) close to the second flywheel (13) and at least vertically distanced from it; the auxiliary flywheel (62), together with the other flywheels, forming the looped path of the cutting wire (15).

The multi-wire machine (1) for cutting stone material (2) according to claims 7 and 8, characterised in that the rough tensioning means (66) comprise at least one actuator (68) connected between the supporting frame (5) and the auxiliary flywheels (62); the rough tensioning means (66) moving the auxiliary flywheels (62) relative to their axis of rotation, between a minimum tensioning position and a maximum tensioning position.

10. The multi-wire machine (1) for cutting stone material (2) according to claim 7 or 9, characterised in that the precision tensioning means (67) comprise a plurality of operating units (74) each connected to each second flywheel (13) and able to translate the axis of rotation of the second flywheel (13), in practice keeping each cutting wire (15) taut independently of the others.

11. The multi-wire machine (1) for cutting stone material (2) according to any of the foregoing claims, characterised in that each cutting wire (15), wound along a looped path, may be mounted on or removed from the respective cutting device (11) directly from the front part (23) of the machine (1).

12. The multi-wire machine (1) for cutting stone material (2) according to any of the foregoing claims, characterised in that the first flywheels (12) of each cutting device (11) are formed by at least one motor-driven drum (75).

13. The multi-wire machine (1) for cutting stone material (2) according to any of the foregoing claims, characterised in that it comprises a plurality of guide rollers (76) rotatably mounted on the supporting frame (5) and, together with the other flywheels, forming the looped path for the cutting wires (15).

14. The multi-wire machine (1) for cutting stone material (2) according to claim 3 and according to any of the other foregoing claims, characterised in that it also comprises a plurality of ducts (77) for conveying cooling water which are mounted on the supporting frame (5) close to the first crosspiece (39) and extend from it towards the base portion (6) of the supporting frame (5); the ducts (77) having a plurality of holes (78) along their length for letting out water.

15. The multi-wire machine (1) for cutting stone material (2) according to any of the foregoing claims, characterised in that it comprises at least one protective guard (80) connected to the supporting frame (5) close to both the first and the second flywheels (12, 13).