CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from Italian patent application no. 102020000028439 filed on November 25, 2020, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD The present invention relates to a wire saw for cutting stone-like materials and the corresponding production method.

More in detail, the present invention relates to a diamond wire for cutting marble and granite. Use to which the following disclosure will make explicit reference without however losing in generality.

BACKGROUND ART

As is well known, almost all the diamond wires for cutting marble and granite currently on the market basically consist of: a multi-strand metal cable closed in a loop; a series of substantially cylindrical tubular-shaped diamond beads that are fitted onto the metal cable at a predetermined and more or less constant distance from each other; and a protective sheath made of polymeric material, which completely coats/covers the metal cable, also interposing itself between the metal cable and the individual diamond beads, so as to prevent direct contact between the diamond beads and the metal cable and at the same time locking the individual diamond beads firmly onto the metal cable.

Each abrasive bead, in turn, basically consists of a rigid tubular sleeve substantially cylindrical in shape, which is made of metal material and is fitted with clearance onto the supporting cable, while remaining locally coaxial to the longitudinal axis of the cable; and an outer bushing substantially cylindrical tubular in shape, which is usually made of sintered diamond, and is fitted onto and rigidly fixed to the tubular sleeve by brazing.

At present, the tubular sleeve is made by turning, starting from a bar of metal material, with the high production costs that this entails.

In PCT application W02014/013450 Al, there is described an alternative method that provides to make the tubular sleeve of the abrasive beads by cold forming, starting from a metal sheet substantially elongated rectangular in shape.

More in detail, the method described in PCT application W02014/013450 Al basically provides to bend/curve the rectangular-shaped metal sheet parallel to its longitudinal axis, so as to bring the two opposite side edges of the sheet into abutment one against the other thus forming a tubular shaped structure; and then welding the two side edges of the metal sheet to each other. As an alternative to welding, it is also possible to glue the two side edges of the metal sheet together.

Unfortunately, the reduction in production costs resulting from the use of the method described in PCT application W02014/013450 A1 proved to be minimal due to the high costs of the piece welding.

The tubular sleeve, in fact, is a piece of small dimensions (in most cases the nominal diameter of the sleeve currently does not exceed 5-6 mm), so the welding of the two opposite side edges of the sheet can only be carried out using high-precision welding machines normally used in the jewellery industry, which are notoriously very expensive and have a low hourly productivity.

DISCLOSURE OF INVENTION

Aim of the present invention is to overcome remedy the drawbacks inherent in the method described in PCT application W02014/013450 A1, so as to drastically reduce the production costs of diamond wires for cutting stone-like materials, clearly without impairing the performance and/or reliability of the tool.

In accordance with these aims, according to the present invention there is provided a wire saw for cutting stone- like or similar materials, of the type comprising: a supporting cable closed in a loop; a series of abrasive beads which are fitted on the supporting cable spaced one after the other; and an outer protective sheath made of a polymeric material, which coats/covers the supporting cable and blocks the abrasive beads in rigid manner on the supporting cable; at least one of said abrasive beads comprising: a tubular sleeve fitted on the supporting cable; and an abrasive bushing which is made of abrasive material and is fitted in rigid manner onto the tubular sleeve; the wire saw being characterised in that the tubular sleeve includes a substantially rectangular-shaped, metal sheet/plate which is provided with a first and a second side edge opposite to one another, and is C-bent so as to form a tubular structure in which said first and second side edges are directly facing one another and are firmly mortised to one another to prevent the opening of the tubular structure. Preferably, though not necessarily, the wire saw is furthermore characterised in that said metal sheet/plate is provided with at least one protruding tab that juts out from a first side edge of the metal sheet/plate, has an enlarged distal head/end, and engages a corresponding complementary- shaped recess/indentation/hollowing that is realized on the facing second side edge of the metal sheet/plate.

Preferably, though not necessarily, the wire saw is furthermore characterised in that said first and second side edges of the metal sheet/plate are firmly and stably mortised to one another via a dovetail or similar coupling.

Preferably, though not necessarily, the wire saw is furthermore characterised in that the metal sheet/plate is C-bent with a substantially constant radius of curvature, in order to form a substantially cylindrical tubular structure. Preferably, though not necessarily, the wire saw is furthermore characterised in that at least part of the internal surface of the tubular sleeve is rugged and irregular.

Preferably, though not necessarily, the wire saw is furthermore characterised in that the internal surface of the tubular sleeve is at least partially knurled. Preferably, though not necessarily, the wire saw is furthermore characterised in that the internal surface of the tubular sleeve is knurled at least along the central segment of the longitudinal through-hole of the sleeve.

Preferably, though not necessarily, the wire saw is furthermore characterised in that the internal surface of the tubular sleeve has a multitude of transversal protruding ridges or ribs and/or a multitude of transversal furrows, incisions or grooves.

Preferably, though not necessarily, the wire saw is furthermore characterised in that the two ends of the longitudinal through-hole of the tubular sleeve have an outwards diverging profile.

Preferably, though not necessarily, the wire saw is furthermore characterised in that the abrasive bushing is fitted on the tubular sleeve so as to lay over the protruding tab/tabs of said metal sheet/plate.

Preferably, though not necessarily, the wire saw is furthermore characterised in that the abrasive bushing is made of a sintered composite material incorporating diamond grains, and/or is fixed in unmovable manner on the tubular sleeve by means of brazing.

According to the present invention there is moreover provided a production method of a wire saw for cutting stone like material, wherein the wire saw comprises: a supporting cable closed in a loop; a series of abrasive beads which are fitted on the supporting cable spaced one after the other, and each of which comprises a tubular sleeve fitted on the supporting cable and an abrasive bushing made of an abrasive material and fitted in rigid manner onto the tubular sleeve; and an outer protective sheath made of a polymeric material, which coats/covers the supporting cable and blocks the abrasive beads in rigid manner onto the supporting cable; the production method of the wire saw being characterised by comprising the steps of:

- cutting a metal sheet of appropriate thickness in order to obtain a substantially rectangular-shaped flat blank; - C-bending the flat blank so as to bring the two opposite side edges of the blank into abutment one against the other, thus forming a tubular structure; and then

- mortising the two opposite side edges of the blank one to the other so as to fix them firmly and form said tubular sleeve.

Preferably, though not necessarily, the production method is further characterised in that the step of mortising the two opposite side edges of the blank to one another envisages inserting, after the C-bending of the blank, one or more protruding tabs which jut out from a first side edge of the flat blank and have an enlarged distal head/end, inside corresponding complementary-shaped indentations/ recesses/hollows that are made on the second side edge of the blank.

Preferably, though not necessarily, the production method is furthermore characterised in that the flat blank is C-bent with a substantially constant radius of curvature, in order to form a substantially cylindrical-shaped tubular structure.

Preferably, though not necessarily, the production method is furthermore characterised in that the flat blank is C-bent by means of cold forming.

Preferably, though not necessarily, the production method is furthermore characterised in that it comprises, before the C-bending of the flat blank, also the step of increasing the surface roughness of a first face of the blank intended to form the inside of the tubular sleeve.

Preferably, though not necessarily, the production method is furthermore characterised in that the step of increasing the surface roughness of the first face of the blank envisages knurling at least a part of the surface of said first face.

Preferably, though not necessarily, the production method is furthermore characterised in that the step of increasing the surface roughness of the first face of the blank envisages making, on said first face, a multitude of transversal protruding ridges or ribs and/or a multitude of transversal furrows, incisions or grooves.

Preferably, though not necessarily, the production method is furthermore characterised in that it comprises, before the C-bending of the flat blank, also the step of thinning the bands of the flat blank that flank said two opposite side edges, so as to reduce the thickness of the flat blank as it moves closer to the side edge.

Preferably, though not necessarily, the production method is furthermore characterised in that said metal sheet has a thickness less than or equal to 1,5 mm.

Preferably, though not necessarily, the production method is furthermore characterised in that it comprises, after making the tubular sleeve, also the steps of: fitting an abrasive bushing onto said tubular sleeve; and then firmly fixing the abrasive bushing on the same tubular sleeve.

Preferably, though not necessarily, the production method is furthermore characterised in that it comprises the steps of: threading a given number of abrasive beads on the supporting cable; joining the two ends of the supporting cable one to the other so as to form a closed loop; and then injection moulding a protective sheath made of polymeric material directly over the supporting cable, so as to block the abrasive beads on the supporting cable.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings, which illustrate a non- limiting embodiment thereof, in which:

- Figure 1 is a perspective view of a segment of a wire saw for cutting stone-like material realized according to the teachings of the present invention;

- Figure 2 is a side view of the wire saw shown in Figure 1, with parts sectioned along the centre plane and parts removed for clarity's sake;

- Figure 3 is a sectional view of an abrasive bead of the wire saw shown in Figures 1 and 2, with parts removed for clarity's sake;

- Figure 4 is a perspective view of the support sleeve of an abrasive bead shown in Figure 3; whereas

- Figures 5 to 8 schematically shown as many steps of the production of the wire saw shown in Figures 1 and 2. BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figures 1 and 2, number 1 denotes as a whole a wire saw for cutting stone-like material, which can be advantageously used for cutting marble and granite. In addition, the wire saw 1 can also be advantageously used for cutting walls and/or items made of stone, reinforced concrete and similar materials.

The wire saw 1 comprises: a central supporting cable 2 of given length, flexible and substantially inextensible, which is closed in a loop in a known manner, is preferably made of metal material and preferably also has a multi-strand structure; a series of tubular-shaped abrasive beads 3, which are externally made of an abrasive material capable of engrave/cutting the stone-like material, and are fitted onto the supporting cable 2 spaced one after the other and preferably also locally substantially coaxial to the supporting cable 2; and an outer protective tubular sheath 4 made of polymeric material, which is made by injection moulding directly onto the supporting cable 2, and coats/ covers the supporting cable 2 so as to substantially completely cover the free segments of the supporting cable 2 and simultaneously block the abrasive beads 3 rigidly onto the supporting cable 2.

In other words, the protective sheath 4 is substantially tubular and has an outer diameter di greater than the nominal diameter d2 of the supporting cable 2, so as to coat/cover and protect the supporting cable 2 substantially along its entire length.

The abrasive beads 3, on the other hand, preferably have a substantially cylindrical tubular shape, and are preferably dimensioned so as to surface/protrude outside the protective sheath 4.

In other words, the abrasive beads 3 preferably have an outer diameter d3 greater than the outer diameter di of the protective sheath 4. Preferably, the protective sheath 4 moreover extends beneath the abrasive beads 3, interposing itself between the supporting cable 2 and the individual abrasive beads 3, so as to prevent direct contact between the abrasive beads 3 and the supporting cable 2. The protective sheath 4 therefore coats/covers the supporting cable 2 without interruption for substantially the entire length of the same cable. More in detail, the abrasive beads 3 have an inner diameter d ₄ slightly greater than the nominal diameter d2 of the supporting cable 2, and are kept locally coaxial and rigidly integral to the supporting cable 2 by the protective sheath 4 that completely fills the space between the two components .

With reference to Figures 1 and 2, moreover the abrasive beads 3 are distributed/spaced on the supporting cable 2 so as to longitudinally divide the protective sheath 4 into, or otherwise delimit on the protective sheath 4, a series of uncovered longitudinal segments of predetermined length l _\ . Each uncovered longitudinal segment of the protective sheath 4 therefore extends without interruptions between two abrasive beads 3 of the wire saw 1. In the example shown, in particular, the abrasive beads

3 are preferably spaced out/distributed substantially evenly along the entire length of the supporting cable 2.

In other words, the axial length l _\ of the various exposed longitudinal segments of the protective sheath 4 is preferably substantially constant.

Preferably each abrasive bead 3 of the wire saw 1 moreover has an axial length I2 less than the axial length l _\ of the exposed longitudinal segments of the outer sheath

4 flanking it, and more generally of all exposed longitudinal segments of the protective sheath 4.

More in detail, the axial length I2 of the abrasive beads 3 is preferably less than half the axial length l of the uncovered longitudinal segments of the tubular sheath 4.

With reference to Figure 2, in the example shown, in particular, the supporting cable 2 is preferably made of steel, and is preferably formed of five or more strands suitably helically wound one on top of the other.

In addition, the supporting cable 2 has a nominal diameter d2 preferably less than 12 mm (millimetres), and preferably, though not necessarily, ranging between 1 and 7 mm (millimetres). Preferably, the difference between the nominal diameter d2 of the supporting cable 2 and the inner diameter d ₄ of the abrasive beads 3 moreover ranges between 0,1 and 1 mm (millimetres).

Preferably, the abrasive beads 3 are moreover distributed on the supporting cable 2 with a substantially constant pitch and preferably also greater than or equal to 15 mm (millimetres). Consequently, the value of the axial length l is preferably substantially equal for all the uncovered longitudinal segments of the tubular sheath 4.

Obviously, the pitch/spacing of the abrasive beads 3 on the supporting cable 2 may also vary along the length of the supporting cable 2.

With particular reference to Figures 2 and 3, at least one and more conveniently each abrasive bead 3 of the wire saw 1 in turn comprises: a tubular supporting sleeve 7, substantially rigid and preferably substantially cylindrical tubular in shape, which is made of metal material and is fitted onto the supporting cable 2, preferably over the protective sheath 4 and/or locally coaxial to the longitudinal axis L of the supporting cable 2; and an outer bushing 8 substantially cylindrical tubular in shape, which is made of abrasive material and is fitted/keyed in a rigid and unmovable manner directly onto the sleeve 7.

Preferably, the axial length of the tubular sleeve 7 is moreover greater than the axial length of the bushing 8, and the outer bushing 8 is preferably positioned substantially in the centre of the sleeve 7. Consequently, the axial length I2 of the abrasive bead

3 corresponds to the axial length of the tubular sleeve 7, while the outer diameter d3 of the abrasive bead 3 corresponds to the outer diameter of the bushing 8. The inner diameter d ₄ of the abrasive bead 3, on the other hand, corresponds to the inner diameter of the tubular sleeve 7.

Preferably, the axial length I2 of the tubular sleeve 7 is moreover greater than or equal to the outer diameter d3 of the surrounding bushing 8.

Preferably, the outer diameter ds of the tubular sleeve 7 is moreover smaller than the outer diameter di of the protective sheath 4, so that the sleeve 7 is locally embedded/incorporated into the protective sheath 4.

In the example shown, in particular, the axial length I2 of the abrasive bead 3, and thus of the sleeve 7, is preferably less than 16 mm (millimetres).

More in detail, in the example shown, the axial length I2 of the abrasive bead 3, and therefore of the sleeve 7, is preferably between 8 and 13 mm (millimetres).

The outer diameter ds of the tubular sleeve 7, on the other hand, preferably ranges between 2,5 and 8 mm (millimetres), while the inner diameter d4 of the tubular sleeve 7 preferably ranges between 2 and 7 mm (millimetres).

Moreover, the difference between the inner diameter d ₄ of the tubular sleeve 7 and the nominal diameter d2 of the supporting cable 2 preferably ranges between 0,2 and 0,3 mm (millimetres). With particular reference to Figure 3, moreover, the longitudinal through-hole 9 of the tubular sleeve 7 is preferably structured so as to maximise the grip of the tubular sleeve 7 on the protective sheath 4.

More in detail, at least a part of the internal surface of the tubular sleeve 7 is preferably rugged and irregular so as to increase the mechanical grip of the tubular sleeve 7 on the protective sheath 4.

In the example shown, in particular, the internal surface of the tubular sleeve 7 is at least partially knurled.

More in detail, the internal surface of the tubular sleeve 7 is preferably knurled at least along the central segment 9a of the longitudinal through-hole 9 of the sleeve.

In addition to or as an alternative to knurling, the internal surface of the tubular sleeve 7 may also have a multitude of transversal protruding ridges or ribs, which are adapted to sink/stick themselves into the protective sheath 4, and/or a multitude of transversal furrows, incisions or grooves which are adapted to be filled with the polymeric material forming the protective sheath 4.

Preferably, the two ends of the longitudinal through- hole 9 of the tubular sleeve 7 also have an outwards diverging profile.

With particular reference to Figures 3 and 4, in addition, the tubular sleeve 7 is basically made up of, or in any case includes, a substantially rectangular-shaped metal sheet/plate 10, which is C-bent/curved so as to form a tubular structure wherein two opposite side edges 10a and 10b of the metal sheet/plate 10 are directly facing and abutting against each other. In addition, the two opposite side edges 10a and 10b of the metal sheet/plate 10 are firmly and stably mortised to one another to prevent the tubular structure from opening.

In other words, the two opposite side edges 10a and 10b of the metal sheet/plate 10 are substantially complementary in shape, and are shaped so as to interlock to one another, thereby realising a mechanical coupling which prevents the subsequent removal of the opposite side edges 10a and 10b themselves .

More in detail, the metal sheet/plate 10 has a nominal thickness preferably less than or equal to 1,5 mm (milli- metres), and is preferably C-bent with a substantially constant radius of curvature, so as to form a substantially cylindrical tubular structure. Preferably, the metal sheet 10 is moreover C-bent by means of cold forming.

With reference to Figures 3 and 4, in particular, the metal sheet/plate 10 is preferably provided with one or more substantially plate-like protruding tabs 11 (two protruding tabs 11 in the example shown), that jut out from the side edge 10a of the metal sheet/plate 10, and have an enlarged head/distal end, i.e. of increased width.

Each protruding tab 11 is adapted to engage/engages a corresponding complementary shaped recess/indentation/ hollowing 12 that is made on the facing and opposite side edge 10b of the same metal sheet/plate 10.

Preferably, the/each recess/indentation/hollowing 12 moreover takes up the whole thickness of the metal sheet/ plate 10 so that the corresponding protruding tab 11 does not protrude from the internal and/or external face of the metal sheet/plate 10, i.e. from the internal and/or external surface of the tubular sleeve 7.

In the example shown, in particular, the metal sheet/ plate 10 is preferably made of steel or bronze, and has a nominal thickness preferably ranging between 0,5 and 1,2 mm (millimetres).

With reference to Figures 3 and 4, preferably the two opposite side edges 10a and 10b of the metal sheet/plate 10 are moreover shaped so as to be firmly and stably mortised to one another via a dovetail or similar coupling.

More in detail, in the example shown the/each protruding tab 11 is preferably shaped in the form of a substantially isosceles trapezoid, and engages a recess/indentation/ hollowing 12 substantially isosceles trapezoid in shape, of complementary dimensions.

Clearly, the/each protruding tab 11 could also be substantially T- or Y-shaped.

With reference to Figures 1, 2 and 3, the outer bushing 8, in turn, is preferably fitted onto the tubular sleeve 7 so as to lay over the protruding tab or tabs 11 of the metal sheet/plate 10.

The bushing 8, in addition, is preferably made of an abrasive material comprising diamond grains.

More in detail, the bushing 8 is preferably made of a sintered composite material incorporating synthetic diamond grains, and is fixed in unmovable manner on the tubular sleeve 7 by means of brazing.

In other words, the abrasive beads 3 are made of sintered diamond on the outside.

The protective sheath 4, on the other hand, is preferably made of thermoplastic polymeric material.

More in detail, the protective sheath 4 is preferably made of a thermoplastic elastomer (TPE).

In the example shown, in particular, the protective sheath 4 is preferably made of a polyurethane-based polymeric material.

In even more details, in the example shown, the protective sheath 4 is preferably made of thermoplastic polyurethane (TPU).

Alternatively, the protective sheath 4 may also be made of a polyamide (PA) based polymeric material such as Nylon, polypropylene (PP) based or other similar polymeric material.

Operation of wire saw 1 is similar to that of currently known diamond wires, and needs no further explanation.

The production of wire saw 1 basically comprises the steps of: threading a given number of abrasive beads 3 on the supporting cable 2; joining the two ends of the supporting cable 2 one to the other preferably, though not necessarily, by splicing, so as to form a closed loop; and then injection moulding a protective sheath 4 made of polymeric material directly over the supporting cable 2, so as to block the abrasive beads 3 on the supporting cable 2.

In addition, before threading the abrasive beads 3 onto the supporting cable 2, the production of wire saw 1 comprises the steps of: making a number of tubular sleeves 7 corresponding to the number of abrasive beads 3 to be threaded onto the supporting cable 2; making a number of abrasive bushings 8 corresponding to the number of abrasive beads 3 to be threaded onto the supporting cable 2; fitting an abrasive bushing 8 onto each tubular sleeve 7; and then firmly fixing the abrasive bushings 8 to the corresponding tubular sleeves 7 preferably by welding or brazing.

With reference to Figures 5 to 8, the production of at least one sleeve 7, and more conveniently all the various tubular sleeves 7 of the abrasive beads 3, in turn comprises the steps of:

- cutting a metal sheet of appropriate thickness in order to obtain a substantially rectangular-shaped flat blank 100;

- C-bending the flat blank 100 so as to bring the two opposite side edges 100a and 100b of the blank 100 into abutment one against the other, thus forming a tubular structure; and then - mortising the two opposite side edges 100a and 100b of the blank one to the other so as to fix them firmly and stably to one another, forming the tubular sleeve 7.

More in detail, the flat blanks 100 is preferably provided with one or more plate-like protruding tabs 110 that jut out from a first side edge 100a of the flat blank 100 and have an enlarged distal head/end, i.e. of increased width; and with one or more recesses/indentations/hollows 120 that are preferably complementary-shaped to the protruding tabs 110, and are made on the second side edge 100b of the blank 100 so that each one is engaged by a corresponding protruding tab 110.

The step of mortising the two opposite side edges 100a and 100b of the blanks one to the other, on the other hand, preferably provides to insert, at the end of the C-bending of the blank 100, the protruding tab or tabs 110 of the blank each within a corresponding recess/indentation/hollow 120 of the blank. Optionally, the step of mortising the two opposite side edges 100a and 100b of the blank one to the other moreover provides alto to deform the protruding tab or tabs 110 of the blank inside the corresponding recess/indentation/hollow 120, so as to adapt the shape of the protruding tab or tabs 110 to that of the respective recess/indentation/hollow 120.

Clearly, after realization of tubular sleeve 7, the production of wire saw 1 provides to fit an abrasive bushing 8 onto the tubular sleeve 7 obtained from the flat blank 100, and then firmly fixing the abrasive bushing 8 on the same tubular sleeve 7 preferably by welding or brazing, so as to obtain the abrasive bead 3.

Preferably, the protruding tab or tabs 110 are moreover shaped in the form of a substantially isosceles trapezoid, so as to realize a dovetail coupling with the corresponding complementary recesses/indentations/hollows 120.

In addition, with reference to Figures 4, 7 and 8, the flat blank 100 is preferably C-bent with a substantially constant radius of curvature, so as to form a substantially cylindrical-shaped tubular structure.

Preferably, the C-bending of flat blanks 100 also takes place by means of cold forming.

In addition, the flat blank 100 is preferably obtained starting from a sheet of metal made of steel or bronze, and/or with a thickness preferably less than or equal to 1,5 mm (millimetres) and more conveniently ranging between 0,5 and 1,2 mm (millimetres). With reference to Figure 6, preferably the production of the tubular sleeves 7 of abrasive beads 3 moreover comprises, before bending the flat blanks 100, also the step of increasing the surface roughness of the face 100c of the flat blank 100 intended to form the inside of the tubular sleeve 7.

More in detail, before the C-bending of the flat blank 100, the production of the tubular sleeves 7 of abrasive beads 3 preferably comprises the step of knurling at least a part of the surface of the internal face 100c of the flat blank 100.

In even more details, before the C-bending of the flat blank 100, the production of the tubular sleeves 7 of abrasive beads 3 preferably comprises the step of knurling at least the central part of the internal face 100c of the flat blank 100.

In addition to or as an alternative to knurling, the production of tubular sleeves 7 preferably comprises the step of making, on the internal face 100c of the flat blank 100 and more in detail on the central portion of the internal face 100c, a multitude of transversal protruding ridges or ribs and/or a multitude of transversal furrows, incisions or grooves.

Finally, before the C-bending of the flat blank 100, the production of the tubular sleeves 7 of abrasive beads 3 preferably also includes the step of thinning, preferably by pressing, the bands of the flat blanks 100 flanking the two opposite side edges 100a and 100b, so as to progressively reduce the thickness of the flat blank 100 as it gets closer to the side edge 100a, 100b.

The wire saw 1 and the method of producing tubular sleeves 7 of abrasive beads 3 described above offer many advantages.

Mortising the two opposite side edges 10a and 10b of the metal sheet/plate 10 one to the other at the end of the C-bending of the same metal sheet/plate 10 prevents having to weld the same side edges 10a and 10b together later, with the substantial saving in time and costs that this entails.

In addition, being located over the protruding tab or tabs 11 of the metal sheet/plate 10, the outer bushing 8 prevents the protruding tab or tabs 11 from lifting and disengaging from the respective recesses/indentations/ hollowings 12, making the mortise between the two opposite side edges 10a and 10b of the metal sheet/plate 10 stronger and more resistant to mechanical stresses.

Moreover, during the moulding of the protective sheath 4, the knurling of the internal surface of the tubular sleeve

7 allows the polymeric material to flow more easily between the abrasive bead 3 and the supporting cable 2, thus speeding up the injection operations.

Finally, the knurled profile of the internal surface of the tubular sleeve 7 prevents axial thrusts being generated during use of the disk saw 1, which tend to move the abrasive bead 3 along the supporting cable 2 and wear out the protective sheath 4.

It is finally clear that modifications and variations may be made to the wire saw 1 and its production method without however departing from the scope of the present invention.

For example, in a more sophisticated not-illustrated embodiment both the protruding tabs 11 and the complementary shaped recesses/indentations/hollowings 12 may be distri buted on both opposite side edges 10a and 10b of the metal sheet/plate 10.

Consequently, the protruding tabs 110 and the complementary recesses/indentations/hollowings 120 should be distributed on both opposite side edges 100a and 100b of the flat blank 100. In addition, the protruding tabs 11 may have different shapes one from the other.