DESCRIPTION

Background of the invention.

The present invention refers to a displacing apparatus for a tool holder assembly of a machine for working block or slab materials, in particular, but not exclusively, stone materials, like, for example, marble and granite.

The invention also refers to a machine for working block or slab materials comprising such displacing apparatus and to a method for working block or slab materials to be carried out by such a machine.

It should be specified that, within the framework of the present description and the appended claims, the term "displacing apparatus" is used to indicate an apparatus adapted to determine any movement of a machine part, either translational or rotational. Moreover, the term "working" is used to generically indicate any operation performed on a piece of material, like for example cutting, squaring or shaping.

Prior art .

Machines for working block or slab materials, and in particular stone materials, essentially comprise a table defining a work surface on which the block or slap to be worked is rested, a tool holder assembly with which a machining tool is associated, a displacing apparatus of the tool holder assembly and a command and control unit equipped with a suitable operator interface. The tool holder assembly has a plurality of supply lines connected to it, for example electrical supply lines or lines for transporting a coolant fluid to the machining tool. The displacing apparatus is mounted on a horizontal gantry that rests on walls or other vertical support structures.

The gantry is mobile on the respective support structures and the displacing apparatus is mobile along the gantry. In this manner the displacing apparatus and the tool holder assembly can be displaced parallel to the work surface along two displacement directions X and Y, perpendicular to each other. In turn, the displacing apparatus can displace the tool holder assembly along a further displacement direction Z perpendicular to the work surface. In order to carry out working operations along both displacement directions X and Y and along oblique directions, it is further provided that the table can be rotated about an axis perpendicular to the work surface, so that the piece of material to be worked can be presented to the working tool according to different angles.

However, the need to use a rotatable table involves constructive complications. Indeed, the displacement devices and the angular position control devices of the table usually lie under the work surface and for this reason operate under unfavourable conditions, both because they have to withstand considerable weights, and because they are constantly invested by working dust and by cooling liquids used during working operations. Furthermore, the use of a rotatable table slows the working times because of the considerable rotational inertia caused by the weight of the table and of the material placed on it.

In an attempt to overcome these drawbacks machines have been developed where the rotation of the table has been replaced by the rotation of the tool holder assembly. In particular, machines for working stone materials are known which have a fixed table and a displacing apparatus for the tool holder assembly that allows rotating the latter about an axis perpendicular to the work surface of the table. Even though this solution allows the aforementioned drawbacks caused by the use of a rotatable table to be overcome, at the present state of art it has not resulted completely satisfactory. In fact, the rotation of the tool holder assembly is limited by the supply lines extended between the gantry supporting the displacing apparatus and the tool holder assembly. Upon rotation of the tool holder assembly the supply lines are inevitably subjected to torsional stress, which must be contained within admissible structural and functional limits, thus limiting the extent of rotation of the tool holder assembly. Practically, in the machines with rotatable tool holder assembly of the prior art, the rotation of the tool holder assembly is limited to angles ranging, at most, between 0° and about 270°. Thus, unlike in machines having rotatable table, this solution results in relative angular positions between working tool and piece of material to be worked that cannot be reached.

International patent application WO 2009/036785, to the Applicant, describes a displacing apparatus for a tool holder assembly able to rotate about a rotation axis perpendicular to a work surface of the relative machine. The tool holder assembly comprises a shaft that, at a first longitudinal end thereof, supports the tool holder assembly, and one or more supply lines connected to the tool holder assembly. In particular, the shaft comprises a window formed around the perimeter at its own side surface to allow the entry of the supply lines into an inner cavity of the shaft itself (a- cavity that is blind at the upper end of the shaft) . Such supply lines comprise a. portion exceeding the length of the shaft. The excess portion can be drawn back into the inner cavity of the shaft, or else it can be expelled from such a cavity, to aid a complete rotation of the shaft itself. The described configuration allows the rotation of the tool holder assembly to be made independent from the supply lines connected to it, so that it is possible to make the tool holder assembly rotate even by 360°, without this causing inadmissible torsional stress on the supply lines.

Other known embodiments are described in US patent 5, 961, 156, in international patent application WO 2006/043294 and in European patent application EP 0260219A.

Summary of the invention.

The Applicant has realised that the machine described in application WO 2009/036785 can be substantially simplified.

The technical problem forming the basis of the present invention is therefore to provide a displacing apparatus for a tool holder assembly of a machine for working block or slab materials that, whilst allowing rotations of 360° of the tool holder assembly about an axis perpendicular to the work surface, is simple in structure, in operation and in maintenance, avoiding inadmissible torsional stress under load of the supply lines connected to the tool holder assembly.

The invention, in a first aspect thereof, concerns a displacing apparatus for a tool holder assembly of a machine for working block or slab materials., the apparatus comprising :

a first shaft provided with a respective inner through cavity, able to rotate about a rotation axis perpendicular to a work surface of said machine and supporting, at a first longitudinal end thereof, said tool holder assembly, and

a transmission element of the rotary motion fixedly connected to said first shaft at a second longitudinal end thereof, opposite said tool holder assembly,

at least one supply line connected to the tool holder assembly, wherein

said tool holder assembly rotates as a unit with said first shaft,

characterised in that said transmission element is provided with a respective through cavity and said at least one supply line extends through the inner cavity of said first shaft and through the inner cavity of said transmission element .

The structure of the displacing apparatus of the present invention advantageously allows the rotation of the tool holder assembly to be made independent from the at least one supply line connected to it, so that it is possible to rotate the tool holder assembly even by 360°, without this causing inadmissible torsional stress on the at least one supply line .

The at least one supply line extends inside the transmission element of the rotary motion and inside the first shaft, in a direction substantially parallel to the rotation axis of the latter. Unlike the apparatus described in application WO 2009/036785, the supply line(s) do not insert into the first shaft through a corresponding side window formed on the outer side surface thereof; in the apparatus according to the present invention the supply line(s) of the tool holder assembly insert axially through the first shaft and through the relative transmission element.

In the apparatus according to the present invention the rotations of the tool holder assembly, imparted by a corresponding rotation of the first shaft, determine minimal torsion of the supply lines. Such torsions remain within the limits of tolerability of each line even when the rotation of the tool holder assembly is at the maximum, i.e. equal to 360°.

Preferred characteristics of the displacing apparatus according to the invention are defined in dependent claims 2-30.

In a preferred embodiment of the displacing apparatus of the invention the first shaft, which supports the tool holder assembly, is able to rotate around the rotation axis of the tool holder assembly and the latter rotates as a unit with the same first shaft.

The structure of the apparatus according to the present invention is particularly compact and organised and it allows possible torsion of the at least one supply line as a consequence of the rotation of the tool holder assembly to be substantially limited, since the at least one supply line is substantially located at the aforementioned rotation axis.

Preferably, the transmission element is a zero backlash reduction gear. The reduction gear comprises a second input shaft and a third output shaft, both provided with respective inner through cavities and communicating with each other. The second input shaft is kinematically connected to a first actuator device and the third output shaft is fitted onto the first shaft that supports the tool holder assembly. The first actuator device is active on the transmission element to transmit the rotary motion to the relative input shaft. Such a rotation is transmitted to the output shaft of the reduction gear, which is kinematically connected to the input shaft through gears, according to a transmission ratio that depends upon the configuration of the gears themselves.

More preferably, the input shaft and the output shaft of the reduction gear are coaxial with one another and also with respect to the first shaft. The inner cavities of the input and output shafts of the reduction gear, which are in communication with one another, open out towards the outside of the reduction gear and into the inner cavity of the first shaft, along the rotation axis, to allow one or more supply lines of the tool holder assemb.ly to pass.

Preferably, the gears of the reduction gear are selected among eccentric gears, planetary gears, cycloidal gears or combinations thereof. The configuration and size of the gears determines the transmission ratio between the input shaft and the output shaft of the reduction gear.

Preferably, the input shaft of the reduction gear comprises coupling means with the aforementioned at least one first actuator device. More preferably, the coupling means comprise a gear wheel or a pulley for respectively coupling with a driving chain and a driving belt of the at least one first actuator device; in this circumstance the first actuator device is separate from the reduction gear and positioned at its side. The gear wheel, or the pulley, can be fitted onto the input shaft of the reduction gear or, alternatively, they can be formed on the outer surface of the input shaft itself. Preferably, the driving belt or chain directly connects the first actuator device with the input shaft of the reduction gear. Alternatively, the coupling means comprise gears, for example gear wheels.

Advantageously, the first actuator device is not positioned at the rotation axis of the tool holder assembly, but is preferably installed alongside such an axis. In this way the route of the supply lines through the reduction gear is not blocked.

Preferably, the at least one supply line is selected among an electric supply line and a fluid supply line, for example for a lubricating fluid.

Preferably, the supply lines are guided by a cable drag chain at least along an outer portion with respect to the transmission element, for example a portion before the entry point of the supply lines into the inner cavity of the reduction gear.

Preferably, the at least one first actuator device comprises an electric motor. More preferably, such an electric motor is of the ^~ brushless type.

In an embodiment, the displacing apparatus according to the present invention comprises at least one second actuator device provided to drive the displacement of the first shaft along a first displacement direction of the relative tool holder assembly, parallel to the rotation axis.

Preferably, the second actuator device comprises a leadscrew actuator having a longitudinal axis substantially parallel to the rotation axis of the tool holder assembly.

More preferably, the displacing apparatus comprises a frame with a fixed part and a mobile cross member that supports the first shaft that supports the tool holder assembly. The nut screw of the leadscrew actuator is fixed to, or formed integral with, the fixed part. Preferably, the second actuator device comprises an electric motor, for example of the . brushless type, to set the screw of the leadscrew actuator in rotation.

Preferably, the displacing apparatus comprises an anti- rotation device having the function of counteracting the rotation of the cross member at the moment of actuation of the leadscrew actuator. Preferably, the anti-rotation device comprises at least one guide having a longitudinal axis substantially parallel to the rotation axis of the tool holder assembly and at least two engagement elements connected to the cross member. The engagement elements slidably cooperate with the guide on opposite sides thereof .

More preferably, the at least two engagement elements are rolling elements.

Preferably, the displacing apparatus comprises a balancing device suitable for balancing the axial stresses acting upon the second actuator device.

.For example, the balancing device comprises an actuator cylinder having a longitudinal axis substantially parallel to the rotation axis of the tool holder assembly. The displacing apparatus comprises a frame with a fixed part and a mobile cross member that supports the first shaft; the actuator cylinder is active between the fixed part and the cross member of the frame.

Preferably, the tool holder assembly comprises an electrospindle suitable for receiving a machining tool and having- a longitudinal axis, and a support body for the electrospindle. The electrospindle is supported by the support ^' body able to rotate about a respective rotation axis perpendicular to a plane defined by the rotation axis of the tool holder assembly and by the longitudinal axis. More preferably, the tool holder assembly comprises a third actuator device having the function of rotating the electrospindle about the respective rotation axis to vary its inclination angle γ with respect to the first shaft. Preferably, the inclination angle γ can vary between about 0° and about 90°.

Preferably, the third actuator device is active along an axis substantially intersecting the longitudinal axis of the electrospindle.

Preferably, the electrospindle is supported by the support body through rotation pins and the third actuator device is at least partially integrated with at least one of such rotation pins.

Preferably, the third actuator device comprises an electric motor and a zero backlash reduction gear.

In a second aspect thereof, the invention concerns a machine for working block or slab materials comprising a displacing apparatus for a tool holder assembly of the aforementioned type.

The advantages of the displacing apparatus of the invention are transferred to the machine for working block or slab materials incorporating such an apparatus, which, in particular, will have operating flexibility substantially equivalent to that of a machine with a rotary table or with side entry of the supply lines into the first shaft, having equal capabilities, whilst still avoiding the aforementioned drawbacks.

Preferred characteristics of the machine for working block or slab materials according to the invention are defined in dependent -claims 32-34, the content of which is fully incorporated here for reference.

In a third aspect thereof, the invention concerns a method for working block or slab materials according to claim 35.

In particular, the method according to the present invention comprises the steps of:

a) providing a work surface (102) and positioning a block or slab (200) to be worked on it;

b) displacing a machining tool (11) associated with a tool holder assembly (10) to perform a working operation on said block or slab (200) ,

wherein said step b) is carried out through a displacing apparatus (1) as described above.

Preferably, step b) comprises the step of displacing the tool holder assembly parallel to its rotation axis, and the step of inserting or withdrawing at least one portion of the supply lines through the transmission element and through the first shaft with which the tool holder assembly is coupled.

Preferably, step b) comprises the step of rotating the tool holder assembly about a respective rotation axis perpendicular to the work surface of the working machine, subjecting the supply line(s) to torsion. As already stated above, the tool holder assembly rotates as a unit with the first shaft and the step of rotating the tool holder assembly is carried out by setting the first shaft in rotation by means of the relative actuator. ^" Advantageously, the displacing apparatus according to the present invention and the relative machine for working block or slab materials can also be used to work moulds used in the field of boat-building for making hulls, keels and structures made from fibreglass or similar materials.

Brief description of the figures.

Further characteristics and advantages of the present invention shall become clearer from the following description of a preferred embodiment thereof, given hereafter, for indicating and not limiting purposes, with reference to the attached drawings. In such drawings :

figure 1 is a schematic perspective view of a machine for working block or slab materials provided with a displacing apparatus for a tool holder assembly in accordance with the invention;

figure 2 is a schematic perspective view of a displacing apparatus for a tool holder assembly in accordance with the invention;

figure 3 is a schematic side view, partially in section, of the displacing apparatus of figure 2;

figure 4 is a schematic front view, partially in section, of the displacing apparatus of figure 2;

figure 5 is an exploded schematic perspective view of a detail of the displacing apparatus of figure 2;

Detailed description of a preferred embodiment of. the invention .

In figure 1, a machine for working block or slab materials, in particular, but not exclusively, stone materials, according to the invention is wholly indicated with reference numeral 100.

The machine 100 essentially comprises a table 101, preferably fixed, defining a work surface 102, a tool holder assembly 10 with which a machining tool 11 is associated, a displacing apparatus 1 of the tool holder assembly 10 and a command and control unit 103 equipped with an operator interface 104.

The table 101 is suitable for supporting a block or a slab 200 of material to be worked.

As an example, the machining tool 11 is represented here in the form of a milling disc to carry out the cutting operations, but it could be any other known machining tool, like . for example an end mill, a grinding wheel, etc.

The displacing apparatus 1 is mounted on a gantry 105 that rests, at its ends, on walls 106 or other suitable support structures, extending in a direction perpendicular to the gantry itself. The displacing apparatus 1 is preferably mobile along the gantry 105 and the latter is preferably mobile parallel to the direction of extension of the walls 106. The displacing apparatus 1, and with it the tool holder assembly 10, can therefore be displaced parallel to the work surface 102 along two displacement directions, respectively indicated with X and Y, perpendicular to one another .

As shall be explained in greater detail hereafter, the displacing apparatus 1 is in turn preferably suitable for displacing the tool holder assembly 10 along a displacement direction Z perpendicular to the work surface 102. Moreover, the displacing apparatus 1 is preferably suitable for displacing the tool holder assembly 10 in rotation about a rotation axis A-A, also perpendicular to the work surface 102, according to a direction of rotation indicated with W.

The structure of the displacing apparatus 1 is shown in figures 2-5. The components of such an apparatus are enclosed in a removable cover shell 8 and supported in a frame having a fixed part 9a and a cross member 9b that is mobile with respect to the fixed part 9a ^■ in the displacement direction Z. A sliding coupling between the displacing apparatus 1 and the gantry 105 is made according to per se known ways at the fixed part 9a of the frame.

The displacing apparatus 1 comprises a shaft 2 that, at a first longitudinal end, supports the tool holder assembly 10. At the opposite longitudinal end the shaft 2 is fixedly connected to the cross member 9b. The shaft 2 is provided with an inner through cavity 20, which connects the two ends of the shaft itself (figures 3-5).

The tool holder assembly 10 has at least one supply line 3, and preferably a plurality thereof (only schematically and partially shown in figures 2-5) connected to it. The supply lines 3 preferably comprise at least one electric supply line and at least one supply line for a fluid, for example water, intended to cool the machining tool during operation .

In accordance with the invention, the supply lines 3 are housed in the inner cavity 20 of the support shaft 2 for the tool holder assembly 1.0 and comprise a portion 30 exceeding the length of the shaft 2 itself. Preferably, the excess portion 30 is arranged at the longitudinal end of the shaft 2 opposite the one that supports the tool holder assembly 10.

In the preferred embodiment illustrated here, the shaft 2 is able to rotate around the rotation axis A-A and the tool holder assembly 10 rotates as a unit with the shaft 2. In this embodiment, therefore, the coupling between the shaft 2 and the cross member 9b must be made so that these two components translate as a unit along the displacement direction Z, but the shaft 2 is free in rotation.

In alternative embodiments (not shown) just the tool holder assembly 10 is able to rotate around the rotation axis A-A, whereas the shaft 2 does not rotate and merely performs a function of supporting the tool holder assembly 10. In the preferred embodiment illustrated here, the supply lines 3 are supported in vertical position, or slightly inclined, at the relative excess portion 30, over the upper end of the shaft 2, by a bracket 40 in turn fixed to the cross member 9b.

As can be seen in detail in figure 3, the supply lines 3 are preferably guided by a cable drag chain 31 at least at the excess portion 30.

The use of the cable drag chain 31 makes it possible to guide the supply lines 3 in an optimal manner and keep them collected together when the machine is operating.

In order to ensure that the supply lines 3 inside the shaft 2 keep their position without riding over one another, in the inner cavity 20 of the shaft 2 at least one bushing (not shown) is supplied, provided with a plurality of through holes each intended to have a respective supply line 3 pass through it.

The displacing apparatus 1 comprises a transmission element 41 coupled with the shaft 2 to give it a rotary motion about the axis A-A in the two directions, as indicated by the arrow . As shown in figure 2, the transmission element 41 is coupled with the shaft 2 at its upper end, opposite to the lower support end for the tool holder assembly 10.

Preferably, like in the embodiment shown in figures 1-5, and in particular in figures 3-5, the transmission element 41 is a zero backlash reduction gear, internally hollow to allow the supply lines 3 to pass directly inside the shaft 2. The reduction gear 41 comprises an input shaft 42 and an output, shaft 43, both provided with respective inner through cavities, visible in figure 3, communicating with one another. The output shaft 43 is fitted onto the shaft 2, in particular it is fitted at its upper end. The input and output shafts 42, 43 are coaxial- with one another and with respect to the support shaft 2 of the tool holder assembly 10. The input shaft 42 and the output shaft 43 are kinematically associated with one another through gears selected among eccentric gears, planetary gears, cycloidal gears or combinations thereof. The gears, .not shown in the attached figures, are housed inside the reduction gear 41. The inner cavity of the input shaft 42 opens out upwards for the passage of the supply lines 3 and downwards to run together in the inner cavity of the output shaft 43.

As an example, a reduction gear suitable for the purpose is marketed by the firm SUMITOMO with the name F2C-Cseries.

The configuration of the gears determines the transmission ratio between the input shaft 42 and the output shaft 43. For example, such a configuration can be selected so that the input shaft 42 is the high speed shaft and the output shaft 43. is the low speed shaft.

The displacing apparatus 1 comprises a first actuator device 17 active on the transmission element 41 to determine the rotation of the relative input shaft 42 about the rotation axis A-A (displacement of the tool holder assembly 10 in the displacement direction W) . Advantageously, the first actuator device 17 is positioned laterally with respect to the reduction gear 41 so as not to block the path of the supply lines 3, and in particular of the relative portion 30. In the embodiment shown in the figures, the actuator 17 is fixedly connected to the cross member 9b.

Preferably, the first actuator device 17 comprises an electric motor 18, more preferably a brushless motor. The shaft 181 (figure 5) of the brushless motor 18, parallel to the axis A-A, is connected to the input shaft 42 of the reduction gear 41 by means of an element 44 _/ for example a belt, or a chain, or one or more gear wheels. Preferably, the input shaft 42 comprises a gear wheel or a pulley 45 (fixedly connected or formed integrally) for the coupling with the chain/belt 44. As explained above, thanks to these characteristics the rotation of the tool holder assembly 10 is made substantially independent from the supply lines 3 connected to it and therefore it is possible to make the tool holder assembly 10 rotate even by 360° around the rotation axis A- A without this causing inadmissible torsional stress under load of the supply lines 3.

The use of the brushless motor 18 and the zero backlash reduction gear 41 advantageously makes it possible to position the tool holder assembly 10 and maintain the positioning reached with high precision, which is an essential condition in order to be able to carry out accurate machining. This requirement is particular strong in the case of cutting operations, in which the machining tool 11 (milling disc) must always be kept perfectly aligned with the cutting line.

Figure 5 shows the apparatus 1 in a partially exploded view. The first actuator device 17 is fixed, preferably removably, to the cross member 9b so that it is decentred with respect to the carcass of the reduction gear 41. At the upper longitudinal end the shaft 2 comprises a horizontal plate 23, provided for the removable connection to the output shaft ^" 43 of the reduction gear 41, for example through conventional threaded fastening elements. The plate 23 is also punctured to allow the inner cavity 20 of the shaft 2 ^" to be passed through by the supply lines 3.

As can be seen in particular in figures 2, 4 and 5, the displacing apparatus 1 comprises an actuator device 5 suitable for displacing the shaft 2 along the displacement direction Z.

The actuator device 5 preferably comprises a leadscrew actuator 50 having a longitudinal axis B-B substantially parallel to the rotation axis A-A.

Preferably, the nut . screw 51 of the leadscrew actuator 50 - Il ^¬ ls fixed to, or formed integrally with, the fixed part 9a of the frame. The screw 52 of the leadscrew actuator 50 is fixed in a freely rotatable manner to the cross member 9b. Therefore, at the moment of rotation of the screw 52 the cross member 9b, and with it the shaft 2 and the tool holder assembly 10, translate along the displacement direction Z with respect to the fixed part 9a of the frame.

The screw 52 is preferably set in rotation by an electric motor 53, more preferably a brushless electric motor.

A zero backlash reduction gear 54 is preferably operatively arranged between the electric motor 53 and the screw 52.

The excess portion 30 acts as a "lung" that allows the supply lines 3 to follow the movement of the tool holder assembly 10 along the direction Z, possibly also requiring the flexing of the chain 31 when the tool holder assembly 10 lowers together with the cross member 9b.

In order to counteract rotations of the cross member 9b at the moment of actuation of the leadscrew actuator 50, the displacing apparatus 1 preferably comprises an anti- rotation device 6 (figure 2) .

In the preferred embodiment of the invention illustrated here, the anti-rotation device 6 comprises at least one guide 60 with longitudinal axis substantially parallel to the rotation axis A-A, and at least two engagement elements 61 connected to the cross member 9b, suitable for slidably cooperating with the guide 60 on opposite sides thereof. Preferably, the engagement elements 61 are revolving elements.

The displacing apparatus 1 also preferably comprises a balancing device 7 suitable for balancing the axial stresses acting upon the actuator device 5. Such axial stresses essentially derive from the weight of the cross member 9b and the components connected to it, in particular the shaft 2 with the tool holder assembly 10..

In the preferred embodiment of the invention illustrated here, the balancing device 7 comprises an actuator cylinder 70 having a longitudinal axis C-C substantially parallel to the rotation axis A-A. The actuator cylinder 70, of the hydraulic or pneumatic type, is preferably active between the fixed part 9a of the frame 9 and the mobile cross member 9b.

As can be seen in particular from figures 2-4, the tool holder assembly 10 essentially comprises an electrospindle 12, suitable for setting in rotation the machining tool 11 associated with it and having a longitudinal axis D-D, and a support body 13 for the electrospindle 12, preferably fork-shaped and integral with the shaft 2. Preferably, the electrospindle 12 is supported by the support body 13 so that it can rotate around a respective rotation axis E-E, perpendicular to a plane defined by the rotation axis A-A of the shaft 2 and by the longitudinal axis D-D of the electrospindle 12, through rotation pins 15.

In the preferred embodiment of the invention illustrated here the tool holder assembly 10 also comprises an actuator device 14 suitable for displacing the electrospindle 12 about the respective rotation axis E-E to vary the inclination angle γ of the electrospindle 12 with respect to the shaft 2. In this way, the machining tool 11 can be displaced according to a further displacement direction, indicated in the figures with R, to easily make, for example, inclined cuts or profile shapes.

The inclination angle γ, measured between the longitudinal axis D-D of the electrospindle 12 and the rotation axis A-A of the shaft 2, can preferably vary between about 0° and about 90°. In figure 3 continuous lines represent the operating configuration taken up by the tool holder assembly 10 when γ=0° (longitudinal axis D-D of the electrospindle 12 parallel to the rotation axis A-A of the shaft 2) and dashed lines represent the operating configuration taken up when γ=90° (longitudinal axis D-D of the electrospindle 12 perpendicular to the rotation axis A- A of the shaft 2) .

Preferably, the actuator device 14 is active along an axis substantially intersecting the longitudinal axis D-D of the electrospindle 12, and more preferably coinciding with the rotation axis E-E thereof.

Preferably, in this case, the actuator device 14 is at least partially integrated with at least one of the rotation pins 15.

Preferably, the actuator device 14 comprises an electric motor 140, more preferably a brushless motor. Moreover, the actuator device 14 preferably comprises a reduction gear (not shown in the figures) .

According to circumstances, the machining tool 11 can be at least partially covered by a protective casing 16.

On the tool holder assembly 10 there can also be a light source 109, preferably a laser, suitable for directing a collimated light ray onto the block or slab 200 to be worked. Such a ray, once the light source 109 has been suitably positioned with respect to the machining tool 11, advantageously allows an operator to display a machining route, in particular a cutting line, in advance on the block or slab 200 to be machined.

The displacement of the displacing apparatus 1 along the gantry 105 (displacement direction X) and of the gantry 105 on the walls 106 (displacement direction Y) is carried out by means of respective actuator devices 107 and 108, which can be seen in figures 3 and 4.

A preferred embodiment of the method for working block or slab materials . according to the invention, able to be actuated through the machine 100 described above, shall now be described.

The method essentially comprises the step of providing the block- or slab 200 to be worked on the work surface 102, preferably fixed, of the machine 100, and then the step of displacing the machining tool 11 associated with the tool holder assembly 10 to carry out a machining operation on the block or slab 200. This displacement step is carried out by means of the displacing apparatus 1 of the tool holder assembly 10, described above. Preferably, the step of displacing the machining tool 11 comprises the step of rotating the tool holder assembly 10 about the respective rotation axis A-A. In this circumstance the supply lines 3 are subject to minimal torsion that in any case does not jeopardise its integrity. Preferably, the tool holder assembly 10 rotates as a unit with the shaft 2 and the step of rotating the tool holder assembly 10, in the clockwise or anticlockwise direction, is actuated by setting the shaft 2 in rotation by means of the actuator 17 and the reduction gear 41. The man skilled in the art will understand that the displacing apparatus 1 has a simple structure whilst still offering the maximum precision and strength.