Patent Description:
In the industry for machining slabs made of stone and/or ceramic material, there has been long known to use machine tools comprising a gantry structure suitable to delimit a work area and at least one horizontal beam on which there is slidably mounted a head for processing the slabs.

The machining operations carried out with such machines are for example cutting, smoothing, contouring, chamfering or the like, and they may require handling, loading/unloading and/or transfer of the products being machined from one area to another of the work area.

Generally, in the processes for cutting the slabs, the machine tool comprises a carriage slidable on the main beam and a cutting head movable above the slab with an electro-spindle to which there is rotatably associated a blade-equipped cutting tool.

Typically, when the cutting head is configured to carry out discontinuous or staggered cuts on two or more adjacent slabs along a horizontal axis, the second slab is spaced from the first slab by a value proportional to the diameter of the blade, so as to prevent the blade from interacting with the transversal peripheral edge of the second slab arranged adjacent to the first slab after cutting the first slab.

However, when the cutting head supports at least one first and one second blade which are substantially vertical and aligned, and having respective centres spaced by a predetermined distance, the distance between the first and the second slab is excessive, resulting in the increase of machining times and decrease in the number of slabs arranged adjacent to each other during machining.

In order to at least partially overcome this drawback, there have been developed cutting apparatuses and methods adapted to vary the height of each blade.

<CIT> discloses an apparatus and a method for cutting porcelain slabs or the like, which provides for a cutting head arranged above a plane for supporting a slab.

The head is provided with a plurality of rotary tools associated with a carriage movable along a horizontal axis and means for the vertical movement of the tools independently from each other.

The method for cutting a slab using such apparatus provides a first step in which the carriage is moved towards the slab to be machined with only one first tool lowered so as to interact with the slab.

The first tool starts to engrave the slab and, subsequently, the second tool is lowered upon exceeding the entry point on the slab. Lastly, the first tool is raised before it exits from the final part of the slab.

<CIT> discloses an apparatus provided with a cutting head equipped with a first and a second disc-shaped blade aligned with respect to each other along a cutting direction and arranged above a work plane suitable to support at least one slab.

Furthermore, the cutting head comprises means for the vertical movement of each blade to lift each blade with respect to the slab when the blade finishes to cut the slab.

A first known drawback of such solutions lies in the fact that the means for the vertical movement act independently on each blade of the cutting head with ensuing increase in the costs for manufacturing the cutting head.

Still, another drawback of such solutions lies in the fact that the means for vertically moving the blades do not allow to reduce the distance between the slabs to be cut.

<CIT> discloses a method of cutting slabs made of stone and/or ceramic material with a cutting head having a tool-holder frame mounted on a carriage movable above the slabs, wherein said frame supports at least one first and one second blade which are substantially vertical and mutually aligned along a longitudinal cutting direction and have respective centres spaced apart by a predetermined distance, said frame being hinged to said carriage by means of a substantially horizontal pin so as to allow the oscillation of said frame and vary the relative height of said blades and the respective cutting depth thereof, the method comprising the following steps:.

In the light of the prior art, the object of the present invention is to solve the technical problem by providing a cutting head which allows to machine several slabs arranged adjacent to each other in which the blades do not damage the subsequent slab after cutting, and at the same time it allows to reduce the distance between the slabs.

The object of the present invention is to solve the aforementioned problem by providing a method for cutting slabs made of stone and/or ceramic material which is highly effective and cost-effective.

A particular object of the present invention is to provide a cutting method of the type indicated above which allows to reduce the distance between two slabs arranged adjacent to each other when cutting them.

Another particular object of the present invention is to provide a cutting method of the type indicated above which allows to carry out discontinuous or staggered cuts on one or more adjacent slabs along a horizontal axis, preventing the blade from interacting with the transversal peripheral edge of a second slab arranged adjacent to the first slab after cutting the first slab.

A further object of the present invention is to provide a cutting method of the type indicated above which makes the operations for pre-cutting and cutting two adjacent slabs particularly quick and simple.

Another object of the present invention is to provide a cutting method of the type indicated above which allows to carry out the pre-cutting and cutting of the slab in a single phase.

A further object of the present invention is to provide a cutting method of the type indicated above which allow to reduce downtime between the discontinuous cut of one slab and the subsequent one, increasing the overall productivity.

A further object of the present invention is to provide a cutting method of the type indicated above which allows to reduce the overall set-up and installation times.

The objects mentioned above and others which will be more apparent hereinafter, are achieved by a cutting method according to claim <NUM>.

The method provides the cutting of slabs made of stone and/or ceramic material using a cutting head having a tool-holder frame mounted on a carriage movable above the slabs along three cartesian axes, wherein the frame supports at least one first and one second blade which are substantially vertical and aligned, and having respective centres spaced apart by a predetermined distance.

The frame is hinged to the carriage by means of a substantially horizontal pin so as to allow the oscillation of the frame and vary the relative height of the blades and the cutting depth thereof.

The method comprises the following steps a) first inclination of the frame by a first predetermined angle with respect to a first slab to be cut so that the first blade is lower than the second blade by a first relative height, b) pre-cutting the first slab using the first blade, c) second inclination of the frame by a second predetermined angle with respect to the first slab so that the first blade is higher than the second blade by a second relative height, d) cutting the first slab using the second blade and e) third inclination of the frame by a third predetermined angle with respect to first slab so that the first blade is higher than the second blade by a third relative height greater than the second relative height so as to prevent the first blade from interacting with a second slab arranged adjacent to the first slab when cutting the first slab in step d).

Advantageous embodiments of the invention are attained according to the dependent claims.

Further characteristics and advantages of the invention will be more apparent in the light of the detailed description of a preferred but not exclusive embodiment of a cutting method like the one mentioned above, shown by way of non-limiting example with reference to the drawings below, wherein:.

With particular reference to the figures, there is shown a method for cutting slabs L made of stone and/or ceramic material using a cutting head, indicated in its entirety with the reference numeral <NUM> and shown in <FIG>.

The cutting head <NUM> may be applied to a multi-axial machine tool <NUM> for cutting or shaping also slabs L made of stone material, such as stone, marble, granite, stony or concrete conglomerates, and to obtain a plurality of suitably shaped portions L', L".

As better shown in <FIG>, the multi-axial machine tool <NUM> may comprise at least one substantially horizontal main beam <NUM> movable along first longitudinal guide means <NUM> anchored to the ground, as described in the patent application <CIT> owned by the applicant.

The machine <NUM> comprises at least one substantially horizontal secondary beam <NUM> operatively associated with the main beam <NUM>, and means for the discontinuous advancement of the slabs L for loading/unloading them, not shown in the figures.

Advantageously, the machine <NUM> may comprise one or more cutting heads <NUM> mounted on the secondary beam <NUM> and slidably movable along second guide means <NUM> associated with the secondary beam <NUM> to carry out cuts along directions parallel to a longitudinal cutting direction D in a single phase, as described below.

The secondary beam <NUM> may be mounted below the main beam <NUM> and can be rotatably coupled to the latter using third guide means <NUM> to rotate around a substantially vertical axis Y and to vary the direction of the common cutting direction D.

Furthermore, the machine tool <NUM> may be arranged above a table for supporting the slabs L being machined having a fixed or movable work plane <NUM>.

In a per se known manner, the slabs L may comprise a substantially flat upper surface LA facing upwards and facing the cutting head <NUM>, a substantially flat lower surface LB resting on the work plane <NUM>, and a maximum thickness s having predetermined and substantially constant dimensions.

As shown in <FIG>, the cutting head <NUM> comprises a carriage <NUM> movable above the slabs L along a first transversal axis X<NUM> and along a second longitudinal axis X<NUM> by means of respective first <NUM> and second guide means <NUM>.

Furthermore, the carriage <NUM> comprises movement means <NUM> which are substantially vertical and can be coupled to the main beam <NUM>, or to the secondary beam <NUM>, of the machine tool <NUM> on which the cutting head <NUM> is mounted so as to move it along a vertical axis Z. Therefore, the carriage <NUM> is movable above the slabs L along the three cartesian axes X<NUM>, X<NUM>, Z.

Advantageously, the cutting head <NUM> comprises a tool-holder frame <NUM> mounted on the carriage <NUM> and that supports at least one first <NUM> and one second blade <NUM> which are substantially vertical and mutually aligned along the longitudinal cutting direction D, and having respective centres C<NUM>, C<NUM> for coupling to respective electro-spindles <NUM>, <NUM> spaced apart by a predetermined distance V.

Preferably, the first <NUM> and the second blade <NUM> have substantially equal diameters.

Furthermore, the frame <NUM> is hinged to the carriage <NUM> by means of a substantially horizontal pin <NUM> so as to allow the oscillation of the frame <NUM> and vary the relative height hR of the blades <NUM>, <NUM> and the respective cutting depth h<NUM>, h<NUM> thereof.

In a preferred embodiment of the invention, schematically shown in figures, the pin <NUM> may be positioned in proximity of a first longitudinal end of the frame <NUM> and above the second blade <NUM> so that the latter has a substantially constant height position in response to the oscillation of the frame <NUM>, therefore solely varying the height of the first blade <NUM>.

In an alternative embodiment, not shown in the figures, the pin <NUM> may be in intermediate position with respect to the longitudinal ends of the frame <NUM>, so that such intermediate position has a substantially constant height position in response to the oscillation of the frame <NUM>.

Therefore, the first cutting blade <NUM> is configured to carry out a pre-cutting T<NUM> in the slab L having a pre-cutting depth h<NUM> with depth which can be adjusted and smaller than the thickness s of the slab L, while the second cutting blade <NUM> is configured to carry out the final cutting T<NUM> of the slab L and therefore with a cutting depth h<NUM> with depth which can be adjusted and equal to or greater than the thickness s of the slab L.

Furthermore, the slabs L may be arranged along the work plane <NUM> side by side and transversely spaced apart by a predetermined value W, so as to allow the discontinuous cutting thereof, or carry out the horizontally staggered cuts, as shown in <FIG>.

As better shown in <FIG>, the cutting method according to the invention is carried out by the cutting head <NUM> so as to prevent the distance W between the slabs L from being excessive. Such excessive distance W is schematically shown in <FIG>.

Therefore, the method according to the invention comprises a first step a) of first inclination of the frame <NUM> by a first predetermined angle α<NUM> with respect to a first slab L<NUM> to be cut so that the first blade <NUM> is lower than the second blade <NUM> by a first relative height hR1, as shown in <FIG>.

Subsequently, the method provides a step b) of pre-cutting the first slab L<NUM> using the first blade <NUM>, as shown in <FIG>.

Furthermore, before the step b) of pre-cutting there is provided a step a<NUM>) of first lowering of the carriage <NUM> with respect to the work plane <NUM> so as to allow the first blade <NUM> to interact with the first slab L<NUM> and carry out the pre-cutting T<NUM>, as shown in <FIG>.

Preferably, the first lowering of the carriage <NUM> occurs in a substantially vertical direction Q.

Opportunely, the step a<NUM>) of first lowering is carried out when the centre C<NUM> of the first blade <NUM> is positioned at the first transversal peripheral edge BA of the first slab L<NUM>.

By way of non-limiting example, during step b) of pre-cutting, the first slab L<NUM> is pre-cut by the first blade <NUM> for a pre-cutting depth h<NUM> which corresponds to <NUM>% of the thickness s<NUM> of the first slab L<NUM>.

Furthermore, during step b) of pre-cutting, the second blade <NUM> does not interact with the first slab L<NUM> and does not even interact with a possible slab L<NUM> positioned preceding the first slab L<NUM> along the cutting direction D.

Subsequently, there are provided a step c) of second inclination of the frame <NUM> by a second predetermined angle α<NUM> with respect to the first slab L<NUM> so that the first blade <NUM> is higher than the second blade <NUM> by a second relative height hR2, and a step d) of cutting the first slab L<NUM> using the second blade <NUM>, as shown respectively in <FIG>.

Suitably, the step c) of second inclination is at least partially carried out during step b) of pre-cutting so that the movement of the cutting head <NUM> along the common cutting direction D is not interrupted.

Furthermore, during said step c) of second inclination there is provided a step c<NUM>) of second lowering of the carriage <NUM> with respect to the work plane <NUM> so as to allow the second blade <NUM> to interact with the first slab L<NUM> maintaining constant the pre-cutting depth h<NUM> of the first blade <NUM>.

Preferably, the second lowering of the carriage <NUM> occurs in a substantially vertical direction Q.

Advantageously, the steps c) of second inclination and c<NUM>) of second lowering are carried out at the same time and when the centre C<NUM> of the second blade <NUM> is positioned at the first transversal peripheral edge BA of the first slab L<NUM>.

By way of non-limiting example, during step d) of cutting, the first slab L<NUM> is cut by the second blade <NUM> for a cutting depth h<NUM> which corresponds to <NUM>% of the thickness s<NUM> of the first slab L<NUM>.

Lastly, the method according to the invention provides a step e) of third inclination of the frame <NUM> by a third predetermined angle α<NUM> with respect to the first slab L<NUM> so that the first blade <NUM> is higher than the second blade <NUM> by a third relative height hR3 greater than the second relative height hR2.

Conveniently, the step e) of third inclination is at least partially carried out during said step d) of cutting and when the centre C<NUM> of the first blade <NUM> is positioned at the second transversal peripheral edge BB of the first slab L<NUM>.

Furthermore, during the step e) of third inclination, the second blade <NUM> interacts with the first slab L<NUM> maintaining constant the cutting depth h<NUM> of the second blade <NUM>.

Following the step e) of third inclination, the cutting of the first slab L<NUM> during the step d) may end when the centre C<NUM> of the second blade <NUM> is positioned at the second transversal peripheral edge BB of the first slab L<NUM>, as better shown in <FIG>.

Therefore, step e) allows to prevent the first blade <NUM> from interacting with a second slab L<NUM> arranged adjacent to the first slab L<NUM> when cutting the first slab L<NUM> in step d).

The first hR1, second hR2 and third relative height hR3 are calculated using the formula hR=V×sinα ± K, wherein K is a predetermined constant relating to the thickness s<NUM>, s<NUM> of the slabs L<NUM>, L<NUM> being processed.

More precisely, the predetermined constant K is a numerical value comprised between <NUM> and the sum between the thickness s of the slab Ks, wherein Ks is a predetermined safety coefficient with value greater than <NUM> and calculated so as to prevent the blades <NUM>, <NUM> from interacting with the slabs L being processed.

It is clear that steps a)-e) of the method according to the invention, and more precisely the values of the predetermined angles α<NUM>, α<NUM>, α<NUM> respectively of steps a), c) and e) for inclining the frame <NUM>, allow to carry out discontinuous or staggered cuts of two or more adjacent slabs along a horizontal axis, preventing the first blade <NUM> from interacting with the transversal peripheral edge BA of a second slab L<NUM> after cutting the first slab L<NUM> by means of the second blade <NUM>.

At the same time, the method for cutting slabs arranged adjacent to each other using a cutting head <NUM> of the type described above, allows to space the first slab L<NUM> from the second slab L<NUM> by the same distance W that would be obtained by cutting the slabs L<NUM>, L<NUM> using a cutting head provided with only one cutting blade.

In the light of the above it is clear that the cutting method according to the invention achieves the pre-established objects and in particular it allows to reduce the distance between two slabs arranged adjacent to each other when cutting them.

The method according to the invention is susceptible to numerous modifications and variants falling within the scope of the attached claims.

Although the method has been described with particular reference to the attached figures, the reference numerals used in the description and in the claims are meant for improving the intelligibility of the invention and do not limit the claimed scope of protection in any manner whatsoever.

Throughout the description, reference to "an embodiment" or "the embodiment" or "some embodiments" indicate that a particular characteristic, structure or element described is comprised in at least one embodiment of the object of the present invention.

Furthermore, the particular characteristics, structures or elements may be combined in any appropriate fashion in one or more embodiments within the scope of the attached claims.

Claim 1:
A method of cutting slabs (L) made of stone and/or ceramic material with a cutting head (<NUM>) having a tool-holder frame (<NUM>) mounted on a carriage (<NUM>) movable above the slabs (L), wherein said frame (<NUM>) supports at least one first (<NUM>) and one second blade (<NUM>) which are substantially vertical and mutually aligned along a longitudinal cutting direction (D) and have respective centres (C<NUM>, C<NUM>) spaced apart by a predetermined distance (V), said frame (<NUM>) being hinged to said carriage (<NUM>) by means of a substantially horizontal pin (<NUM>) so as to allow the oscillation of said frame (<NUM>) and vary the relative height (hR) of said blades (<NUM>, <NUM>) and the respective cutting depth (h<NUM>, h<NUM>) thereof, the method comprising the following steps:
a) first inclination of said frame (<NUM>) by a first predetermined angle (α<NUM>) with respect to a first slab (L<NUM>) to be cut so that said first blade (<NUM>) is lower than said second blade (<NUM>) by a first relative height (hR1);
b) pre-cutting the first slab (L<NUM>) using said first blade (<NUM>);
c) second inclination of said frame (<NUM>) by a second predetermined angle (α<NUM>) with respect to the first slab (L<NUM>) so that said first blade (<NUM>) is higher than said second blade (<NUM>) by a second relative height (hR2);
d) cutting the first slab (L<NUM>) using said second blade (<NUM>);
e) third inclination of said frame (<NUM>) by a third predetermined angle (α<NUM>) with respect to the first slab (L<NUM>) so that said first blade (<NUM>) is higher than said second blade (<NUM>) by a third relative height (hR3) greater than said second relative height (hR2) so as to prevent said first blade (<NUM>) from interacting with a second slab (L<NUM>) adjacent to the first slab (L<NUM>).