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Title:
MACHINE FOR WIRE CUTTING STONE MATERIAL
Document Type and Number:
WIPO Patent Application WO/2009/098721
Kind Code:
A1
Abstract:
A machine (1) for wire cutting stone material comprises a supporting element (11), at least one connecting element (12) connected to the supporting element (11), at least one motor-driven pulley (7) and a tensioning device (13). Mounted on the connecting element (12) and free to rotate about respective axes of rotation (B and C) there is at least one pair of coplanar idle pulleys (8). A cutting wire (9) is wound in a loop around the motor-driven pulley (7) and the idle pulleys (8). The tensioning device (13) comprises means (14) for moving the connecting element (12) on the supporting element (11), in a direction (D) substantially parallel with the plane in which the idle pulleys (8) lie, between a cutting wire (9) minimum tensioning position and maximum tensioning position.

Inventors:
PELLEGRINI MARCO (IT)
Application Number:
PCT/IT2008/000072
Publication Date:
August 13, 2009
Filing Date:
February 05, 2008
Export Citation:
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Assignee:
PELMINE S R L (IT)
PELLEGRINI MARCO (IT)
International Classes:
B23D57/00; B28D1/08
Domestic Patent References:
WO2000005021A12000-02-03
WO2007063559A12007-06-07
WO1999000210A11999-01-07
Foreign References:
DE29819851U11999-02-04
EP1024314A12000-08-02
ES2167228A12002-05-01
IT1180403B1987-09-23
Attorney, Agent or Firm:
PONCHIROLI, Simone (Via G. Garibaldi 19, Verona, IT)
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Claims:

Claims

1. A machine (1) for wire cutting stone material, comprising: at least one pair of idle pulleys (8), coplanar and mounted on a connecting element (12) connected to a supporting element (11) and free to rotate about respective axes of rotation (B, C); at least one motor-driven pulley (7) substantially coplanar with the two idle pulleys (8); at least one cutting wire (9) wound in a loop around the motor-driven pulley (7) and the idle pulleys (8); and at least one cutting wire (9) tensioning device (13); the machine being characterised in that the connecting element (12) can move relative to the supporting element (11) in a sliding direction (D) substantially parallel with the plane in which the idle pulleys (8) lie, and in that the tensioning device (13) comprises means (14) for moving the connecting element (12) relative to the supporting element (11), in the direction (D), between a cutting wire (9) minimum tensioning position and maximum tensioning position.

2. The wire cutting machine (1) according to claim 1, characterised in that the idle pulleys (8) are positioned one above the other and respectively on opposite sides of the supporting element (11).

3. The wire cutting machine (1) according to claim 1 or 2, characterised in that the two idle pulleys (8) have the two axes of rotation (B, C) lying in a substantially vertical plane.

4. The wire cutting machine (1) according to any of the foregoing claims, characterised in that the movement means (14) comprise devices (15) for connecting element (12) sliding relative to the supporting element (11).

5. The wire cutting machine (1) according to claim 4, characterised in that the sliding devices (15) comprise at least one actuator (16) which acts to make the connecting element (12) and the pair of idle pulleys (8) perform a translatory movement relative to the supporting element (11).

6. The wire cutting machine (1) according to claim 5, characterised in that the actuator (16) is driven by means of a fluid.

7. The wire cutting machine (1) according to claim 5, characterised in that the actuator ( 16) is driven electrically.

8. The wire cutting machine (1) according to any of the claims from 4 to 7, characterised in that the sliding devices (15) comprise at least one track (21), having two rails (21a) and integral with the supporting element (11) or with the connecting element (12), on which the connecting element (12) or the supporting element (11) respectively slides.

9. The wire cutting machine (1) according to claim 8, characterised in that the connecting element (12) has two slides (22), each sliding on a rail (21a) of the track (21) belonging to the supporting element (11).

10. The wire cutting machine (1) according to any of the foregoing claims, characterised in that the connecting element (12) comprises a bar (19) centrally connected to the supporting element (11) and with the main axis substantially vertical.

11. The wire cutting machine (1) according to claim 8, characterised in that the idle pulleys (8) are rotatably mounted at the ends (20) of the bar (19).

12. The wire cutting machine (1) according to any of the claims from 1 to 9, characterised in that the connecting element (12) comprises at least one laminar body (24) extending mainly so that it is flat and substantially vertical, being connected to the supporting element (11).

13. The wire cutting machine (1) according to claim 12, characterised in that the idle pulleys (8) are rotatably mounted close to the edges (25) of the laminar body (24).

14. The wire cutting machine (1) according to claim 12 or 13, characterised in that the connecting element (12) comprises a pair of laminar bodies (24) respectively positioned one on one side and one on the other side of the idle pulleys (8).

15. The wire cutting machine (1) according to any of the claims from 12 to 14, characterised in that the laminar body (24) has a central housing (26) for laminar body (24) sliding on the supporting element (11).

16. The wire cutting machine (1) according to claim 15, characterised in that the housing (26) can be opened to allow disconnection of the laminar body (24) from the supporting element (11).

17. The wire cutting machine (1) according to claim 16, characterised in that the laminar body (24) has means for preventing its accidental disconnection from the supporting element (11).

18. The wire cutting machine (1) according to any of the foregoing claims, characterised in that its also comprises a containment body (28), mounted on the supporting element (11) and on which the connecting element (12) slides.

19. The wire cutting machine (1) according to any of the foregoing claims, characterised in that the supporting element (11) comprises a central beam (23) extending substantially horizontally and parallel with the axes of rotation (B, C) of the idle pulleys (8), to allow the connection of a plurality of connecting elements (12) and relative pairs of idle pulleys (8).

20. The wire cutting machine (1) according to claims 18 and 19, characterised in that the containment body (28) performs a translatory movement along the central beam (23), allowing the connecting element (12) and idle pulleys (8) to move in the direction that is horizontal and parallel with the axes of rotation (B, C).

21. The wire cutting machine (1) according to claim 19 or 20, characterised in that the distance between two adjacent connecting elements (12) can be modified by inserting spacers (29).

22. The wire cutting machine (1) according to claim 19 or 20 or 21, characterised in that the connecting elements (12) are fitted with sliding blocks (30) positioned between one connecting element (12) and the adjacent one.

23. The wire cutting machine (1) according to any of the foregoing claims, characterised in that the idle pulleys (8) have a wear band (17) on the outer circumference.

24. The wire cutting machine (1) according to claim 23, characterised in that the wear band (17) has a groove (18), allowing it to house the cutting wire (9).

25. The wire cutting machine (1) according to any of the foregoing claims, characterised in that it also comprises: a supporting structure (2);

a frame (3), mounted on the supporting structure (2) and on which the supporting element (11), the connecting element (12) and the motor-driven pulley (7) are fixed; a carriage (6) on which a block (5) of stone material can be positioned; and means for vertical sliding of the frame (3) and the carriage (6) relative to one another.

26. The wire cutting machine (1) according to any of the foregoing claims, characterised in that it also comprises at least one control unit for its operation.

27. The wire cutting machine (1) according to claim 26, characterised in that the control unit comprises at least one sensor (31) for detecting the position of the connecting element (12) and of the pair of idle pulleys (8) relative to the supporting element (11).

28. The wire cutting machine (1) according to claim 25 or 26, characterised in that the control unit comprises a system for controlling cutting wire (9) tensioning.

29. The wire cutting machine (1) according to any of the foregoing claims, characterised in that the direction (D) of sliding is substantially horizontal.

30. The wire cutting machine (1) according to any of the foregoing claims, characterised in that the movement means (14) vary the position of the connecting element (12) relative to the motor-driven pulley (7).

Description:

Description

Machine for wire cutting stone material

Technical Field

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

Background Art

Such machines generally comprise one or more cutting devices, each consisting of a diamond cutting wire wound in a loop around at least two pulleys, commonly known as "flywheels", at least one being motor-driven, the wire rotating on them at high speed.

Each cutting device also has a tensioning system which guarantees tensioning of the individual cutting wire during the entire cutting operation.

The problems of tensioning the diamond wire are generally solved by moving the shaft which supports an idle flywheel using suitable movement means. In the case of multi-wire machines, and more in particular machines using a plurality of flywheels mounted on the same shaft, in a prior art tensioning system all of the idle flywheels, on which the wires are wound, are tensioned simultaneously. This type of tensioning, performed identically and simultaneously on all of the idle flywheels, may result in various disadvantages. In particular, if the diameters of the flywheels are even slightly different from those of the similar adjacent flywheels, there could be unwanted wear or deformation of the wire, the flywheels may wear, etc.

Therefore, systems were developed which allow individual and independent tensioning for each idle flywheel.

An example such a tensioning device, which allows independent tensioning of all of the individual cutting wires, is described in patents WO 2007063559 and EP 1 024 314.

In the latter patent, there is a step of "rough" tensioning of the wire, carried out by making all of the idle flywheels perform a translatory movement and a step of "fine" tensioning of the wire. The latter tensioning is guaranteed by a hydraulic cylinder, connected between the idle flywheel and a part fixed relative to the flywheel, which is supplied with pressurised oil in such a way as to cause it to extend. Said extension causes a consequent movement of the idle flywheel relative to the fixed part, in a direction such that it lengthens the path of the cutting wire.

However, said solution also has several disadvantages, important above all in the case of multi-wire machines. First, the dimensions of the tensioning device do not allow the flywheels to be positioned side by side very close to one another. Second, said solution makes it quite difficult to remove an individual flywheel. If substituting a flywheel or the relative wire, all of the flywheels on one side of the flywheel to be substituted also have to be removed from the machine. This results in a considerable amount of labour and increases the risk of the tensioning systems being damaged during removal and subsequent mounting of the flywheels.

Finally, said solution requires that the tensioning device be positioned centrally to the flywheel, which therefore must have dimensions which make it difficult to produce, mount and maintain.

Another prior art device for tensioning the wire in machines for cutting stone material is that with operation of at least one pulley on the portion of wire between two idle flywheels (for example described in patents WO0005021, ES2167228 and IT1245309). The pulley is driven by an actuator (electric, hydraulic or pneumatic) which presses it against the cutting wire, thus tensioning the wire.

Said prior art solution also has the disadvantage of the tensioning device having considerable dimensions, which in multi-wire machines does not allow the idle flywheels to be positioned side by side very close to one another.

Disclosure of the Invention

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

In particular, the technical purpose of the present invention is to provide a machine for wire cutting stone material which allows simple and optimum adjustment of cutting wire tensioning.

Another aim of the present invention is to provide a machine for multiple wire cutting of stone material which allows easy substitution of a flywheel or the relative wire.

Another aim of the present invention is to provide a machine for wire cutting stone material which allows simultaneous cutting of two or more slabs, the slabs being very thin. Another technical purpose of the present invention is to provide a machine for wire cutting stone material which makes available a tensioning device of simple construction, which is reliable and relatively inexpensive.

These aims and others, more apparent in the description which follows, are achieved by the machine for wire cutting stone material comprising the technical features described in one or more of the claims herein.

Brief Description of the Drawings

Further features and advantages of the invention are more apparent from the detailed description of a preferred, non-limiting embodiment of the machine for wire cutting stone material according to the present invention.

The invention is described below with reference to the accompanying drawings, provided by way of example only and, therefore, without limiting the scope of the invention, and in which:

Figure 1 is a front view with some parts transparent of a first embodiment of a machine for individual wire cutting of stone material made in accordance with

the present invention;

Figure 2 is an enlarged view, from the opposite side compared with Figure 1, of the wire tensioning device of the machine of Figure 1;

Figures 3 and 3 a illustrate a view according to the cross-section III - III of Figure 2, of the wire tensioning device of the machine of Figure 1 in the two positions respectively for maximum and minimum tensioning;

Figure 4 is a view according to the cross-section FV - IV of Figure 2, of the wire tensioning device of the machine of Figure 1;

Figure 4a is an enlarged view of the detail labelled IVa in Figure 4; Figure 5 is a front view with some parts transparent of a second embodiment of a machine for multiple wire cutting of stone material made in accordance with the present invention;

Figures 6 and 6a are enlarged views of the wire tensioning device of the machine of Figure 5 in the two positions respectively for minimum and maximum tensioning;

Figure 7 is a view of the machine of figure 5 according to the cross-section VII - VII of Figures 6 and 6a;

Figure 8 is an enlarged view of the detail labelled VIII in Figure 7;

Figure 9 is an enlarged view of the detail labelled EX in Figure 7; Figure 10 is a side view, according to the cross-section X - X of Figures 6 and 6a, of the device for connecting the pulleys of the machine of Figure 5 with a single pair of pulleys; and

Figure 10a is a side view, according to the cross-section X - X of Figures 6 and 6a, of the device for connecting the pulleys of the machine of Figure 5 with a plurality of pairs of pulleys.

Detailed Description of the Preferred Embodiments of the Invention

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

The machine 1 comprises a supporting structure 2, on which a frame 3 is mounted.

Mounted on the frame 3 there is at least one cutting device 4 for making at least one cut in a block 5 of stone material. The block 5 can be positioned on a carriage 6 which is inserted inside the supporting structure 2, preferably below the frame 3.

In the preferred embodiments illustrated in the accompanying drawings, the frame 3 can slide on the supporting structure 2 and moves along a substantially vertical direction A. In that way, the cutting device 4, integral with the frame 3, makes the cut in the block 5 of stone material positioned on the carriage 6. In another embodiment (not illustrated in the accompanying drawings) the frame 3 is rigidly fixed to the machine 1 supporting structure 2 and the carriage 6 can move in the substantially vertical direction A, so that the block 5 of stone material is cut. hi the various embodiments the supporting structure 2 is fixed to the floor (as in the embodiments illustrated in the accompanying drawings) or it may move on a horizontal track, on which it is mounted in such a way that it can run on wheels. In this case, there are movement means (of the known type) operatively connected to the structure so that it can move along the track when the command is given. The cutting device 4 in turn comprises at least one motor-driven pulley 7 and at least one pair of idle pulleys 8, free to rotate respectively about two axes of rotation B and C. The motor-driven pulley 7 and the pair of idle pulleys 8 are substantially coplanar and lie in a plane that is substantially vertical, therefore they all rotate about substantially horizontal axes of rotation. Wound in a loop around the motor-driven pulley 7 and the pair of idle pulleys 8 there is at least one diamond cutting wire 9. The latter is made to rotate at high speed along a direction of rotation W and, in that way, makes cuts in the block 5 according to a known technique. To keep the cutting wire 9 in position and under tension, the motor-driven pulley 7 and the pair of idle pulleys 8 are preferably spaced and positioned on the cutting device 4 on opposite sides relative

to the block 5.

In the embodiments illustrated, the cutting device 4 also comprises a plurality of additional rotary elements 10 (for example consisting of pulleys) smaller and coplanar with the motor-driven pulley 7 and the pair of idle pulleys 8, the function of the additional rotary elements being to guide the cutting wire 9 in the best possible way.

The cutting device 4 also comprises a supporting element 11, integral with the frame 3, to which a connecting element 12 is connected. The pair of idle pulleys 8 is mounted on the connecting element. In the cutting device 4, a tensioning device 13 is operatively active on the connecting element 12, and consequently on the pair of idle pulleys 8, keeping the cutting wire 9 under tension. Said tensioning device 13 comprises means 14 for moving the connecting element 12 on the supporting element 11.

The movement means 14 act in a direction D that is substantially horizontal and parallel with the plane in which the pair of idle pulleys 8 and the motor-driven pulley 7 lie, between a cutting wire 9 minimum tensioning position (Figures 3a and 6) and a cutting wire 9 maximum tensioning position (Figures 3 and 6a).

Therefore, in the minimum tensioning position, the pair of idle pulleys 8 is in the position closest to the motor-driven pulley 7 (pair of idle pulleys 8 moved to the left in Figures 1 and 5); whilst in the maximum tensioning position the pair of idle pulleys 8 is in the position furthest away from the motor-driven pulley 7 (pair of idle pulleys 8 moved to the right in Figures 1 and 5).

In the preferred embodiments illustrated in the accompanying drawings, the idle pulleys 8 are fixed on the connecting element 12 in such a way that the plane passing through the two axes of rotation B and C of the idle pulleys 8 is substantially vertical.

Moreover, the pair of idle pulleys 8 is preferably mounted on the connecting element 12 with one idle pulley 8 higher than the supporting element 11 and with the other idle pulley 8 lower than the supporting element 11. The connecting element 12 is preferably moved on the supporting element 11 centrally between

the two idle pulleys 8: in this way the force applied by the movement means 14 causes equal cutting wire 9 tension on the two idle pulleys 8.

The movement means 14 comprise an actuator 16 which acts in such a way that it causes the connecting element 12 and, consequently, also the pair of idle pulleys 8 mounted on it, to perform a translatory movement relative to the supporting element 11. The actuator 16 is preferably a hydraulic cylinder, as in the accompanying drawings, or a pneumatic cylinder or an electric device. The sliding of the connecting element 12 on the supporting element 11 is advantageously guaranteed by the presence of sliding devices 15 between the two elements (explained in more detail below).

Advantageously, the idle pulleys 8 also have, on the outer circumference, a replaceable wear band 17, preferably made of a different material to the rest of the idle pulley 8. In this way, during operation, the inner structure of the idle pulleys 8 is not ruined and worn. Said wear band 17 preferably has a special groove 18 on the outer circumference which allows it to house the cutting wire 9 and avoid its separation from the idle pulley 8.

A control unit (not illustrated) is also set up to control operation of the machine 1 as a whole; in particular it is designed to control the movement of all of the machine 1 moving parts. The control unit advantageously comprises a system for controlling cutting wire 9 tensioning, for example using load cells. -

In accordance with the present invention, the machine 1 also comprises at least one sensor 31 for detecting the position of the connecting element 12 and the pair of idle pulleys 8 relative to the supporting element 11.

The sensor 31 preferably detects the position of the pair of idle pulleys 8 relative to the minimum and/or maximum tensioning position.

Advantageously, the signal indicating the position of the pair of idle pulleys

8 is then sent to the control unit, which is programmed to vary the speed of movement of the frame 3 relative to the supporting structure 2, depending on the position of the pair of idle pulleys 8 detected by the relative sensors and, consequently, according to the cutting wire 9 tensioning, in known ways (see for

example patent WO2007063559).

In accordance with a first embodiment (illustrated in Figures 1, 2, 3, 3a, 4 and 4a), the machine 1 for wire cutting stone material has a single cutting device 4. Therefore, the machine 1 has a single pair of idle pulleys 8 and a single cutting wire 9.

On the same side as the motor-driven pulley 7, said embodiment also has an additional idle pulley 8. The latter and the motor-driven pulley 7 are positioned on the cutting device 4 opposite the pair of idle pulleys 8.

As illustrated in Figure 2, the connecting element 12, on which the idle pulleys 8 are positioned, comprises a bar 19. The bar 19 is positioned with the main axis substantially vertical and the two idle pulleys 8 are rotatably mounted at the two ends 20 of the bar 19.

The bar 19 is centrally connected to the supporting element 11. In this embodiment, as illustrated in Figures 3, 3a, 4 and 4a, the sliding device 15, between the supporting element 11 and the bar 19, advantageously comprises a track 21, integral with the supporting element 11, on which the bar 19 is hooked and slides. To allow sliding, the bar 19 has, in a central position, two slides 22 which each slide on a rail 21a of the track 21 belonging to the supporting element 11. In another embodiment, not illustrated in the accompanying drawings, the track 21 is integral with the bar 19 and one or more slides 22 are integral with the supporting element 11.

Figures 3 and 3 a show the bar 19 and the pair of idle pulleys 8 in two different positions: in Figure 3, in the cutting wire 9 maximum tensioning position, with the actuator 16 in the minimum extension position; in Figure 3 a, in the cutting wire 9 minimum tensioning position, with the actuator 16 in the maximum extension position.

As illustrated in the accompanying drawings, in the embodiment indicated, the actuator 16 is preferably a hydraulic actuator. In accordance with a second embodiment (illustrated in Figures 5, 6, 6a, 7,

8, 9, 10 and 10a), the machine 1 for wire cutting stone material has a plurality of cutting devices 4. Therefore, the machine 1 has a plurality of connecting elements 12, with a pair of idle pulleys 8 connected to each one, and a plurality of cutting wires 9, positioned parallel with one another so that they can simultaneously make a plurality of cuts in the same block 5 of stone material.

Said embodiment also has a plurality of motor-driven pulleys 7, each at a pair of idle pulleys 8 and for each cutting wire 9. hi an alternative embodiment, in place of the set of motor-driven pulleys 7, a single grooved drum is used on which all of the cutting wires 9 slide. Hereinafter the term motor-driven pulley 7 shall also always refer to the case in which the motor-driven pulley in reality consists of a grooved drum.

Advantageously, in said embodiment, the supporting element 11 is shared by all of the cutting devices 4. The supporting element 11 comprises a central beam 23, extending substantially horizontally and parallel with the axes of rotation B and C of the idle pulleys 8. In this way, the plurality of connecting elements 12 with the relative pairs of idle pulleys 8 is connected to the central beam 23.

In the preferred embodiment illustrated in the accompanying drawings, each connecting element 12 consists of a pair of laminar bodies 24, positioned respectively one on one side and one on the other side of the respective pair of idle pulleys 8. hi an alternative embodiment, not illustrated in the accompanying drawings, a single laminar body 24 is used as the connecting element 12 for each pair of idle pulleys 8.

The laminar body 24 mainly extends so that it is flat, along a plane that is vertical and parallel with the plane containing the respective pair of idle pulleys 8, and is substantially C-shaped. The pair of idle pulleys 8 is rotatably mounted close to the edges 25 of the laminar body 24 with one idle pulley 8 higher than the central beam 23 and the other idle pulley 8 lower than the central beam 23.

The laminar body 24 therefore has a housing 26 inside which the central beam 23 is positioned. The housing 26 is substantially rectangular and suitable for

horizontal sliding of the laminar body 24 on the central beam 23, in the direction D that is substantially horizontal and parallel with the plane in which the pair of idle pulleys 8 lies.

The housing 26 preferably has a removable fastener 27, to prevent the laminar body 24 from disconnecting from the central beam 23. Therefore, advantageously, the housing 26 can be opened if the relative laminar body 24 with the pair of idle pulleys 8 has to be removed from the machine 1. Said procedure is relatively simple and may be carried out for any pair of idle pulleys 8, without interfering with the other pairs of idle pulleys 8. In this way, each cutting device 4 can be removed independently of the others.

Mounted between the central beam 23 and the laminar bodies 24, there are containment bodies 28, mounted around the central beam 23 and on which the laminar bodies 24 slide in the direction D.

As illustrated in Figures 5, 6 and 6a, the actuator 16 is advantageously positioned outside the connecting element 12 in such a way as to facilitate maintenance and checks on it. The actuator 16 is fixed on the fastener 27, integral with the laminar body 24 and acts on the containment body 28, integral with the central beam 23.

In another embodiment, not illustrated in the accompanying drawings, the actuator 16 is fixed on the containment body 28, and therefore is integral with the central beam 23, and acts on the laminar body 24.

The actuator 16 is preferably positioned off centre on the fastener 27. In that way, there being a plurality of cutting devices 4, each having a pair of idle pulleys 8 and preferably a pair of laminar bodies 24 enclosing the idle pulleys 8, it is possible to bring the cutting device 4 as close together as possible, positioning the actuators 16 of the adjacent cutting devices 4 in such a way that they are offset, as illustrated in Figure 5 which illustrates two adjacent cutting devices 4.

Figures 6 and 6a show the laminar body 24 and the pair of idle pulleys 8 in two different positions: in Figure 6, in the cutting wire 9 minimum tensioning position, with the actuator 16 in the maximum extension position; in Figure 6a, in

the cutting wire 9 maximum tensioning position, with the actuator 16 in the minimum extension position.

As illustrated in Figures 10 and 10a, each pair of laminar bodies 24, and the relative pair of idle pulleys 8, is positioned on a containment body 28. Each containment body 28 can slide, with the relative pair of laminar bodies 24 and the relative pair of idle pulleys 8, on the central beam 23 in a direction that is horizontal and parallel with the axes B and C. In this way it is possible to vary the distance between one cutting device 4 and the next, thus varying the thickness of the cut made in the block 5. To set the distance between one cutting device 4 and the next, advantageously spacers 29 are inserted. Said spacers 29 are positioned on the central beam 23, between one containment body 28 and the next (as illustrated in Figure 10a).

Moreover, if during machine 1 operation not all of the various cutting device 4 are used, those not used may be parked next to each other, thus reducing the space occupied (as illustrated in Figure 10a).

Moreover, to prevent adjacent cutting devices 4 from obstructing one another, the containment body 28 has a thickness, in the direction that is horizontal and parallel with the axes B and C, slightly greater than the thickness of the pair of laminar bodies 24 between which the pair of idle pulleys 8 is enclosed. In that way, when one cutting device 4 moves towards another, only the containment bodies 28 and not the laminar bodies 24 rest against one another.

Advantageously, the laminar bodies 24 have sliding blocks 30, on the opposite surface to that where the idle pulleys 8 are present. Said sliding blocks 30 are therefore positioned between one laminar body 24 and the adjacent one to facilitate their reciprocal movement.

Operation of the machine 1 for wire cutting stone material follows from the above description.

The above-mentioned tensioning device 13, in both the first and the second embodiments, can be used not just to tension the cutting wire 9, but also to

position the cutting wire 9 on the cutting device 4. The sliding which can be performed by the connecting element 12 on the supporting element 11 is sufficient to allow, in the minimum tensioning position, the cutting wire 9 to be easily positioned or removed from the cutting device 4. The present invention brings important advantages.

First, the machine for wire cutting stone material disclosed allows simple and balanced adjustment of the cutting wire tensioning.

Second, when two or more cutting devices are present, this machine allows easy substitution of the pairs of idle return pulleys or the relative wire without having to remove other idle pulleys present on the machine.

Third, the machine for wire cutting stone material disclosed allows simultaneous cutting of two or more slabs, the slabs being very thin.

Moreover, the machine for wire cutting stone material disclosed allows "rough" tensioning and "fine" tensioning of the cutting wire using a single tensioning device.

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