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Title:
SELF-CLEANING CHAIN WITH MODULAR OUTER LINK FOR ORNAMENTAL STONES CHAIN CUTTING MACHINES
Document Type and Number:
WIPO Patent Application WO/2018/172884
Kind Code:
A1
Abstract:
Cutting chain for ornamental stones chain cutting machines, comprising a plurality of inner (2) and outer (1) links alternating with respect to each other, the outer links (1) being of the modular type, in two or three pieces. Around the articulation between the links (1, 2), an interspace (8) is formed which is narrow enough to prevent the entry of the material generated by the cutting, which could cause the articulation to jam. Close to such interspace (8), a projection (10) of the outer link (1) is provided to avoid the free rotation of the chain in the direction opposite to its natural curvature around the drive pinion. In order to prevent vibrations of the chain, poor machining, deformation of links, or even the breaking of the chain, even in the long-term, means are provided for pushing and ejecting the material generated by the cutting, in a position adjacent to the inlet of the interspace. Such means will form wedges (12) which crush the material with an action concentrated at the tip and above all they push it laterally even if it had hardened during the period the chain was inoperative, and in any case the action of the wedges (12) is cyclic and automatic given that it draws advantage from the cyclic rotary motion between the links of the chain during the operation of the chain cutting machine. Thus, the chain becomes a self-cleaning chain. Preferably, the wedges (12) are arranged under the projections (10) of the outer link.

Inventors:
FANTINI LUIGI (IT)
Application Number:
PCT/IB2018/051685
Publication Date:
September 27, 2018
Filing Date:
March 14, 2018
Export Citation:
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Assignee:
FANTINI SUD SPA (IT)
International Classes:
B28D1/12; B27B33/14
Domestic Patent References:
WO2016020722A12016-02-11
WO2013139632A12013-09-26
Foreign References:
IT1241916B1994-02-01
US4619172A1986-10-28
ITRM20130330A12014-12-08
ITRM20130173A12014-09-23
Attorney, Agent or Firm:
FIAMMENGHI, Eva et al. (Via delle Quattro Fontane 31, Roma, IT)
Download PDF:
Claims:
Claims

Cutting chain for ornamental stones chain cutting machines, comprising inner links (2) and outer links (1) which are alternating and mutually connected through articulation pins (5), the outer links (1) being formed by three portions (3a, 3b, 3c), including two lateral (3a, 3c) and a third central (3b) separating the two lateral portions (3a, 3c) of the outer link (1) from each other, wherein

said central portion (3b) is integrally joined to a first (3a) of the two lateral portions (3a,

3c) and it is removably connected to the other lateral portion (3c), or

said central portion (3b) is removably connected to both lateral portions (3a, 3c), and wherein,

said three portions (3a, 3b, 3c) of each outer link (1) form plates assembled to each other in parallel fashion so as to form an intermediate space housing two respective round- shaped longitudinal ends (6, 6) of contiguous inner links (2, 2),

said round-shaped longitudinal ends (6, 6) having a shape substantially complementary to two concavities (7, 7) formed on a lower side and at the longitudinal opposite ends of said central portion (3b), so as to create respective labyrinth-like interspaces (8) with substantially constant thickness also during the operation of the chain and with shape adapted to that of the two concavities (7, 7), so as to prevent the entry of the material (9) generated by the cutting of the ornamental stone,

said central portion (3b) of an outer link (1) having two projections (10, 10) at two opposite free ends of said two concavities (7, 7), said projections (10, 10) serving as a barrier against the material (9) generated by the cutting of the ornamental stone, and as an abutment for preventing the free rotation of the chain in the direction opposite to the natural bending thereof around the drive pinion and to the idler wheel/pinion, said projections (10, 10) extending, in a straight section of the chain on which the links (1, 2) are in axis i.e. aligned, substantially up to a juxtaposed surface of a respective recess (11) formed on an upper wall of the contiguous inner link (2) in a position adjacent to a corresponding round-shaped longitudinal end (6),

characterised in that

one or more projections (10) of one or more outer links (1) of the cutting chain has - at the lower part - a wedge (12) for pushing and ejecting the material (9) generated by the cutting, cooperating with a respective flat juxtaposed surface of a corresponding recess (11), or

one or more surfaces of a corresponding recess (11) of an inner link (2), cooperating with a projection (10) which is thus flat at the lower side and belongs to an outer link (1), having a wedge-shaped element for pushing and ejecting the material (9) generated by the cutting,

and in that one or more lateral portions (3a, 3c) of one or more outer links (1) has one or more openings (13) for the lateral ejection of the material generated by the cutting arranged laterally with respect to said pushing and ejecting wedge as well as substantially at the same height as the latter.

Cutting chain according to claim 1, characterised in that all projections (10) of all outer links (1) of the cutting chain have - at the lower part - a wedge (12) for pushing and ejecting the material generated by the cutting, said wedges (12) being made of a single piece with the respective outer link (1), said wedges (12) having a constant shape of the cross-section thereof with respect to a longitudinal extension axis of the corresponding outer link (1), said constant shape of the cross-section of said wedges (12) being that of an isosceles triangle, said cutting chain further being characterised in that the surfaces of all recesses (11) of all inner links (2), cooperating with the respective wedges (12) to eject the material generated by the cutting, are flat.

Cutting chain according to claim 1, characterised in that all projections (10) of all outer links (1) of the cutting chain have - at the lower part - a flat surface cooperating with the respective pushing and ejecting wedge-shaped surfaces, which are formed in a single piece with the respective inner link (2), on the surface of the recess (11) of the latter, said cutting chain further being characterised in that said pushing and ejecting wedge has a cross-section with constant shape transversely to a longitudinal extension axis of the corresponding inner link (2), said constant shape being an isosceles triangle.

Cutting chain according to any one of the preceding claims, characterised in that said openings (13) for the lateral ejection of the material generated by the cutting are ejection slots (13) formed on the opposite longitudinal ends of the lateral portions (3a, 3c) of the outer links (1) of the chain, said ejection slots (13) being open towards the corresponding longitudinal end of the outer link (1), i.e. outwards.

Cutting chain according to any one of the preceding claims, characterised in that said central portion (3b) of the outer link (1), integrally joined to a first (3a) of the two lateral portions (3a, 3c) and removably connected to the other lateral portion (3c), is preferably laser- welded to said first lateral portion (3a) after they are obtained.

Cutting chain according to claim 5, characterised in that mechanical fixing means (4a) for removable connection with the other opposite lateral portion (3c) are introduced from the outer side of the other lateral portion (3c) only, and in the case of screws, such screws (4a) have a long-threaded stem that extends for at least most of the thickness or at least for the entire thickness of the central portion (3b) of the outer link (1) of the cutting chain.

Cutting chain according to any one of the preceding claims, characterised in that - at the top part - an outer link (1) of the chain has a relief with chamfer (14) inclined downwards and outwards with respect to the outer link (1), said chamfer (14) being provided at the longitudinal end of the outer link (1) opposite with respect to the cutting tool.

8. Cutting chain according to any one of the preceding claims, characterised in that the pushing and ejecting wedges, on the inner and/or outer links, and the lateral ejection openings or slots, may be obtained, through a machining process from the full, using a mechanical tool, or an electrical discharge machining tool, laser machining tool, ultrasonic machining tool, waterjet cutting tool or a flame cutting tool, and the combinations thereof, or by adding material even different from that of the primary piece, and the combinations thereof, through a manual, automatic or semi-automatic machining process.

Description:
"Self-cleaning chain with modular outer link for ornamental stones chain cutting machines"

Description Technical field

The present invention generally regards the technology of ornamental stones chain cutting machines, like the ones normally used in ornamental stones (marble, etc.) excavation quarries. Specifically, the invention regards the chain formed by inner links and outer links that carry the cutting tools.

The inventive concept generally applies to chains of all types with all types of insert-holders and cutting inserts, to any type of arrangement of the cutting inserts on the chain, to all methods of application of the insert on the insert-holder (removable and non-removable type). Thus, as regards the invention is not limited to the embodiments described and illustrated in the figures, which are used solely for illustrative and non-limiting purposes. Furthermore, the chain of the invention can be mounted on any arm of the chain cutting machine of any type known in the prior art regarding the excavation of ornamental stones in quarries. The materials the chain of the invention can be made up of are the ones usually used in the industry (thus even the ones known in the prior art for obtaining inserts, insert- holders, elements for connection between the inner and outer links, etc.).

Thus, as regards the manufacturing and assembling methods, the materials, the arrangement of the components, the fixing means, the designer may choose based on the particular needs also using equivalent means without departing from the scope of protection of the invention and from the specific inventive concept thereof. Prior art

In conventional chains of ornamental stones chain cutting machines the inner and outer links are alternating forming the endless chain, which, as known, is mounted in the guide of the orientable arm of the machine. The orientable arm has a pinion for actuating the chain at one end thereof and a pinion or idler wheel of the chain at the other end (free end).

Having been in the industry for several decades, the Applicant of the present patent application is the proprietor of several national (Italian) and international patents and utility models.

In particular, the Italian patent application No. RM2013A000330 (Italian patent granted on 11/09/2015 which is considered entirely incorporated to the present description as concerns any technical detail) regards a chain that overcomes the problem related to the slipping off of the articulation pin which connects the inner link to the adjacent outer link. The outer link consists of three parts and the articulation pin has two steps which prevent it from slipping off. There are fixing means (normally screws) locking the parts of the outer link to each other.

In another Italian patent application, RM2013A000173 filed on 22/03/2013, also granted at national level, the outer link consists of two modular monolithic components.

To define the technical problem on which the present invention is based, herein reference is made to Figs. 13A-13B-13C attached to the present patent application, corresponding to figures 1B-1C-1A of patent application n° RM2013A000330 mentioned above but whose reference numbers were changed (and mostly cancelled) to simplify the illustration.

What the two technical solutions proposed in the previous documents of the prior art share in common are the two concavities (100, 100) present at the ends of the lower wall of the central part (101) of each outer link (102, 101, 102'), wherein each of these concavities cooperates with a corresponding profile end (103) of an adjacent inner link (108), thus leading - so to say - to a labyrinth path (104) with a minimum clearance, such to prevent the entry of debris/sludge resulting from cutting the ornamental stone. Furthermore, the concavities (100, 100) form (at the opposite ends of the central part of the outer link) two projections (105, 105) so as to prevent free rotation in the direction opposite to the natural curvature thereof around the drive pinion.

Furthermore, each inner link (108) has - at the upper part - a respective recess (106) suitable to receive the projections (105) in a straight configuration (see Fig. 13 A) of the links of the chain. Additionally, the upper part (107, 107) of the end of the inner link (108) can be rounded on both sides thereof, to facilitate the exit of any impurities, of extremely small dimensions, which could accumulate in the interspace (104) of the concavities (100).

All this is already known to those skilled in the art and is shown in Figures 13A-13B-13C which represent this prior art.

In order to better understand the meaning and the problems/disadvantages of this prior art specific reference is made to Fig. 13B attached. The upper part of this Fig. 13B shows only a portion (of the known chain), comprising an outer link and two inner links (108, 108) connected in an articulated fashion; it should be observed that the part 102' of the modular outer link (102, 101, 102') was removed/demounted in Fig. 13B to show the internal. In the lower part of Fig. 13B, the situation is illustrated when said chain portion is no longer straight and the inner links (108, 108) rotate given that the chain portion is forced to rotate around the pinion/idler wheel. In the latter situation the sludge cannot enter into the interspace 104 given that it is too narrow, but it can deposit and be crushed (compacted) under the projections (105) in the recess (106), at the opposite ends of the latter. Furthermore, if the chain is not used for quite some time, for example a few hours or days, the sludge generated during the machining of the ornamental stone may form actual extremely hard crusts, so that the chain portion in which this happens no longer takes the straight position of Fig. 13B, at the top, but forms a small curve/rounding thus making the cutting operation less regular, generating vibrations and noise, and creating actual stresses on the links of the chain. In particular, such stresses act during the operation of the chain both on the lower part of the projection (105), directly through the compacted layer of sludge, and indirectly on the articulation (109), as instantly observable.

It has been observed that said stresses in particular cause a deformation on the central part (101) of the inner link (102, 101, 102'), which - deforming at the end in the direction of the arched arrow F - ends up breaking the fixing screw (110; Fig. 13B) of the outer link.

Even by providing for vibrational sensors or other sensors (optical, etc.) the operation of the chain could be stopped in good time, before causing further damage, but this would not solve the problem at the source but only serve as preventive measure.

Summarising, it is clear that the complications described above are inadmissible for the good operation of the chain, and given that demounting the entire chain for maintenance thereof implies (even when planning to replace just one link) inoperative times and considerable loss of productivity, the inventor of the present invention tried to overcome the problem at the source, preventing the disadvantageous effects thereof.

Thus, an object of the present invention is to provide a chain with modular outer link, for ornamental stones chain cutting machines, capable of preventing the accumulation of sludge and the ensuing hardening thereof in the recess formed on the upper wall of the inner link. Another object of the present invention is to use simple means and technical solutions, so as to avoid substantially increasing production costs with respect to conventional chains.

Summary of the invention

The preceding technical problem was brilliantly overcome - and its drawbacks eliminated - by providing for means for the push and lateral ejection of the material generated by the cutting (sludge/dust). In this manner, such material does not have time to compact under the projection of the outer link, given that it is ejected by the chain in advance. Even though the material has dried and hardened (forming a crust) on the chain, to an extent of becoming as hard as the ornamental stone to be cut, during an inoperative period (even only just for a few hours) of the cutting machine, given that the chain was at contact with the material alongside the arm that supports it, the push and lateral ejection means of the invention almost immediately break the crust, thus the chain portion (or section) consisting of the links in question is automatically realigned, avoiding instability, vibrations or worse damage (deformations, etc.) to the chain, even prior to said chain portion/section reaching a pinion of the orientable arm. Said push and lateral ejection means, to be described herein shortly, have the function of cyclically pressing on the material which is normally deposited on a recess of the inner link in the position adjacent to the inlet of the interspace which extends around the articulation of the two adjacent links (outer, inner). Such pressure cyclic effect, of potential breaking of the crust (if the material has hardened), and of lateral ejection of the material, occurs periodically and automatically due to the rotation, around a pinion of the guide and support orientable arm, and to the subsequent realigning of each chain portion, facilitated by the means of the invention.

Thus, the invention provides a "self-cleaning" chain, which exploits the same movement i.e. the kinematics of the roto-translational motion of the chain around and between the drive and idler pinions.

The means of the invention form wedges having a constant section profile in the direction of longitudinal extension of the outer link. Such wedges for pushing and lateral ejection of the material generated by the cutting act through the tip thereof with linear extension, with a tip load, on the material that is deposited on the inner link at the inlet with the interspace, and they simultaneously press - with the isosceles triangle inclined walls thereof - against the material, pushing it towards the sides of the chain, where other means of the invention (openings, slots) are provided for which enable the material to exit from the chain, or rather from the outer link thereof, without any interference. The wedges for pushing and lateral ejection of the material will be described in detail in the detailed description that follows; each of them preferably consists of a single piece with the outer link, under one of the projections.

The invention provides means which, with reasonable costs, enable overcoming a quite considerable problem of the industry. Basically (in the preferred embodiment of the invention) it is a matter of modifying the outer links only, while all other components of the chain may remain unvaried.

Brief description of the drawings

The present invention will now be described more in detail with reference to the attached drawings which show a particular non-restricting and non-limiting embodiment of the invention, wherein:

FIGURE 1 is a front view of a chain portion of the invention (with a part of the outer link intentionally removed to simplify the description), which illustrates the problem of accumulation of sludge/dust under the projection of the outer link at the inlet of the interspace, during the relative rotation between the inner link and the outer link;

FIGURE 2 is a perspective view of the same chain portion represented in Fig. 1, which shows the solution of the problem, i.e. the lateral ejection of sludge/dust from the chain;

FIGURE 3 A is the vertical section of III-III of Fig. 1, which shows the shape (in cross- section) of the wedge for pushing the material (sludge/dust) for ejection;

FIGURE 3B is a view corresponding to an enlarged detail of Fig. 3 A but in which the action is shown of the wedge for pushing and the lateral ejection of the material;

FIGURE 4 A shows the outer link of the invention only, in a front view;

FIGURE 4B is a detail of FIG. 4A, in which the lateral slot for the ejection of the material is clearly shown;

FIGURE 5 is an exploded perspective view of the modular outer link only of the self- cleaning chain of the present invention;

FIGURE 6 is a front view of the outer link of Fig. 5, partly assembled, without a lateral component, to make the relative position between the pushing wedge and the lateral slot for the exit of the material (sludge/dust) visible;

FIGURE 7 is a top plan view of the outer link fully assembled;

FIGURE 8 is a front view of a first component (or left side, or left lateral part) of the modular outer link of the invention;

FIGURE 9 is a vertical cross-sectional view along line IX-IX of Fig. 8;

FIGURE 10 is a front view of the other component (or right side, or right lateral part) of the modular outer link of the invention;

FIGURE 11 is a cross-sectional view along line XI-XI of Fig. 10;

FIGURE 12A is a front view of the central part or component of the outer link comprising the two concavities (already known) and - at the end - the two pushing and ejection wedges (present invention);

FIGURE 12B is a top plan view (arrow P) according to Fig. 12A; FIGURE 12C is an end view (arrow Q) on the rear part - with reference to the direction of motion V (see Fig. 12 A) of the chain - which shows the shape of the wedge for pushing to eject the material;

FIGURE 13 A is homologous to the one of Fig. 1, but showing the chain of the prior art; FIGURE 13B illustrates the operation of the chain of the prior art of Fig. 13 A, which prevents the entry of the material (sludge/dust) into the outer link (interspace (104) between the inner and outer link around the articulation (109) but it does not fully overcome the problem related to the malfunctioning of the chain due to the accumulation and hardening of the sludge;

FIGURE 13C is an exploded perspective view of the modular outer link and the inner link according to the prior art previously represented in Figs. 13A, B.

Detailed description of a preferred embodiment of the present invention

In the present detailed description of a preferred embodiment of the invention the materials and methods for manufacturing the chain subject of the invention will not be described in detail, given that they are known to a man skilled in the art. Reference shall only be made to the fact that the components of the links that are currently preferably obtained by cutting and machining steel sheets bound with high yield and optimal resistance to wear (cutting with flame, water or laser). The inserts and the insert-holders will not be described and shown in the figures either, so as to avoid complicating the description and the figures; furthermore, the shape and arrangement thereof may widely vary, as known to those skilled in the art. The man skilled in the art may modify (even extensively) the solutions proposed and described, without departing from the scope of protection of the present invention.

Thus, the embodiment herein proposed and currently preferred exclusively serves for putting the man skilled in the art in the condition to fully understand and implement the invention based on the inventive concept and relative disclosure.

Reference numbers indicating the same components are always the same in all drawings so as to avoid complicating the description. When using spatial references such as "upper" and "lower", etc., regarding the chain shown in the figures, it should always be borne in mind that when the chain rotates around an idler pinion or drive pinion, these spatial references change to "lower" and "upper" respectively, or vice versa, and thus they shall not be deemed in absolute but rather relative sense, depending on the context of the figures.

The verb "to comprise" referring to a characteristic, shall always be considered in patent terms, i.e. that other characteristics not mentioned may be present, they too, besides the explicitly mentioned characteristic.

Now, the chain of the present invention will be described with reference to Figs. 1 up to 12, in a preferred embodiment thereof.

The endless chain of the present invention, in this preferred but non-limiting or non-binding embodiment, comprises a plurality of outer links 1 and inner links 2. Fig. 2 shows by way of example only a chain portion formed by an outer link 1 and by two inner links 2, 2 which project therefrom and thus visible only partly. Obviously, as known to the man skilled in the art, the inner 1 and outer 2 links follow each other in an alternating fashion, and they will not be shown as a complete chain to avoid complicating the drawing. As shown in Figure 5, the outer link 1 consists of (in the present preferred and non-binding embodiment) three parts, 3a, 3b, 3c fixed to each other by means of fixing means 4a, 4b introduced into suitable holes. Such fixing means can be of various types (conical counter-sunk head screws, etc.), they are used for joining the parts of the outer link to each other and resist against forces during the cutting of the ornamental stone. The assembly shown in Fig. 5 is already known, besides the innovative characteristics to be described hereinafter.

Fig. 1 represents the same chain portion of Fig. 2, in which the part 3c of the outer link 1 was however removed with the aim of making a side of the two adjacent inner links 2, 2 entirely visible, was however removed.

As known, the outer link 1 is the one that supports the tool holder and the tool, which were not represented for the sake of comfort. The arrow R indicates in Fig. 1 the advancement direction of the endless chain. The inner links 2 are connected in an articulated fashion to the outer links 1 by means of articulation pins 5 inserted into respective holes 5' and 5" of the outer and inner links, respectively. The shape of the pins 5 is the one previously described in the documents of the prior art mentioned above (see articulation pin (111) of Fig. 13C), i.e. with a cylindrical central portion with larger radius and two cylindrical lateral portions (end portions) with smaller radius, so as to guarantee an abutment with the inner sides of the parts 3a and 3c of the outer link, respectively. Figs. 1 and 2 intentionally show an inclined position of the left inner link 2 with respect to the outer link 1, the arrow R thus indicating, besides the advancement direction, also a relative rotation between the links; thus, this for example is the moment in which the chain portion represented in Figs. 1 and 2 leaves the drive pinion and moves towards the free end of the orientable arm of the cutting machine.

Exactly like in the prior art mentioned in the introduction of the present document, the round-shaped ends 6, 6 of each inner link 2 copy the profile of two concavities 7, 7 formed - at the lower part - in the intermediate part 3b of the outer link (see Figs. 5 and 6), thus the interspace 8 (see Fig. 1) between the concavities 7 and the rounded ends 6, 6 leaves a substantially constant minimum space/clearance during the movement of the chain, such to prevent, as described in the aforementioned prior art documents, the entry of the material (sludge/dust) around the articulation hinge. This is already described in the aforementioned prior art; the damage that the entry of the material into the outer link around the articulation hinge could cause is clear to the man skilled in the art thus this problem (jamming of the hinge, etc.) will not be addressed further.

However, the material (sludge, dust), indicated with number 9 in Figs. 1 and 2, though not entering into the interspace 8 it may however deposit under the projections 10 both during the cutting and, in particular, during the periods of inoperativeness of the chain cutting machine. Thus, the material 9 shown in Figs. 1 and 2, or during the cutting or during such periods of inoperativeness, in a chain portion which has (temporarily) the inclination shown between the links, may deposit and in particular form crusts at the ends of the upper recess This entails the impossibility for the chain portion to completely reacquire a straight shape even in the straight guide section of the orientable arm; this leads to poor operation, vibrations, stresses on the projection 10 (made of a single piece on the intermediate part 3b of the outer link) and on the respective fixing means 4a, instability of the chain deriving from such deformation, etc.

While in the prior art (Fig. 13A) the projection (105) has a constant cross-sectional thickness and thus presses on the material 9 which deposits beneath it, compacting it more and more through the respective lower flat surface of such projection (105), the present invention provides means for averting this event.

According to the present invention, a wedge 12 for pushing and ejecting the material 9 is formed under the projection 10.

Preferably, said wedge 12 forms a single piece with the lower part of the projection 10, i.e. it is made of a single piece with the intermediate part 3b of the chain.

Preferably, the wedge 12 is symmetrical (isosceles triangle), in transversal section, as shown in particular in the sections of Fig. 3 A, B, thus giving rise to a linear tip compression action line on the material, as shown in particular in Fig. 3B, in which the material 9 is literally broken/crushed by the tip 13 of the wedge and ejected laterally at the same time (Fig. 3B), each time the chain links are realigned with respect to each other at the exit from the idler pinion or at the exit from the drive pinion, respectively (see for example arrow R, Fig. 1). Figure 2 in particular shows the ejection (arrows S) of the material from the chain, caused by the pushing and ejection wedge 12 of the present invention.

According to Fig. 4A and 4B (detail of Fig. 4A), and Fig. 2, the lateral parts 3a and 3c (also see Fig. 5) of the modular outer link 1 each have slot openings 13 which enable the exit of the material on both sides of the ornamental stone cutting chain. Obviously, there are a total of four slots 13, i.e. a pair of slots 13 is provided at one end of the outer link 1 and the other pair of slots 13 is provided on the other end of the of the outer link 1, i.e. at the opposite end with respect to the cutting tool (not shown). Same case applies to the wedge 12, associated to the respective pair of slots 13, 13, wherein a first wedge 12 for pushing and ejecting the material is provided for close to the cutting tool (not shown) while a second wedge 12 for pushing and ejecting the material is provided for at the opposite end of the outer link 1 of the chain with respect to the cutting tool.

It should be observed that in the prior art (Fig. 13C) such slots 13 had not been provided for and there was no reason for the existence thereof given that the technical problem was another.

In Fig. 13A (prior art) the base of the projection (105) - with flat-shaped surface at the lower part - substantially reaches the upper wall of the recess (106) of the outer link (108). Also, in the present invention said wedge 12 for pushing and ejecting the material preferably has its tip 13 which substantially reaches (i.e., touches) the upper flat surface of the recess 11 of the inner link 2. This is due to the fact that the cutting chain is more stable during operation. Lastly, in the cutting chain according to the present invention the upper end of the outer link on the opposite side with respect to the cutting tool has a chamfer 14 inclined downwards and outwards with respect to each outer link 1. Such chamfer 14 on the outer link 1 is for example visible in Fig. 4A. As observable in Figs. 2 and 5 such chamfer 14 in this embodiment consists of three identical chamfers formed in the respective parts 3a, 3b, 3c. The chamfer 14 is not present in the corresponding relief (112) of the prior art (for example see Fig. 13A) and it serves to prevent the consumption of the material of the relief (112) which occurs - in case of some types of tools - during the operation of the cutting chain of the prior art. Especially in small chains, the chamfer 14 could be absent, given that no wear of structural material is observed at this point.

To summarise, the operating tests carried out clearly showed that the cutting chain of the present invention no longer revealed the drawbacks of the prior art described above. This means that when the various chain portions leave the drive or idler pin, respectively, entering into the straight guide section (upper or lower respectively) of the orientable arm, the wedge 12 immediately presses on the material 9 with a force such to break the material and, in any case, such to cyclically push it towards the external in the direction of the slots 13, thus preventing accumulation thereof on the recess 11 of the inner link and beneath the projection 10.

As easily understandable by a man skilled in the art, the non-limiting and non-binding description outlined above may be subjected to numerous modifications.

For example, though the outer link preferably consists of three parts, especially due to production reasons, the outer link could also consist of only two modular parts, wherein one of the portions (3a or 3c) is integrally joined to the intermediate part 3b and it is fixed to the other part (3c or 3a) by means of mechanical fixing means 4a and 4b (screws or any other means). In an alternative embodiment, the assembly process is once again firstly carried out in three separate parts 3a - 3b - 3c, thus welding the lateral plate 3a or 3c by means of a laser or other means to the intermediate plate 3b, so as to obtain a single piece (3a + 3b or 3c + 3b) and lastly mechanically fixing such single piece to the remaining lateral plate 3c or 3a. The advantage thereof lies in the possibility to use the mechanical fixing means (preferably only on one side) with a longer stem, and thus - for example - screws with a longer threaded stem or with several threads, or in other words, a screw with greater fastening. As a matter of fact, in Figure 5 two screws 4a inserted from opposite sides but on the same geometrical axis inevitably have a smaller stem and lesser fastening.

Furthermore, the man skilled in the art immediately observes that though the preceding figures and the relative description take into account an outer link with two pushing and ejecting wedges acting on cooperating/juxtaposed flat surfaces of the recess 11 of the adjacent inner links 2, the arrangement of these means could be inverted, obtaining the same results. In other words, the wedges for pushing and ejecting the material generated from the cutting of the ornamental stone could be provided for on the upper surface of the recess 11 (in a position adjacent to the rounding 6 i.e. at the feet thereof), and in this case the lower surfaces of the projections 10 of the outer link would be flat like in the prior art.

For the sake of clarity and coherence of the description expressions such as "upper" and "lower", "high" and "low", or the like were also used in the claims that follow; obviously they shall be considered with reference to the attached figures and to the description, given that in operating mode the links of the chain can normally take arbitrary spatial orientations. The present invention expresses the basic inventive concept which consists of using a wedge for pushing and ejecting the material arranged as described and claimed.