Excavation machine comprising cutting discs and corresponding cutting process

Abstract

Excavation machine comprising cutting discs and corresponding cutting method. The invention relates to an excavation machine comprising a cutting head (24) with: a first drum (40') and a second drum (40'') positioned side by side, close to each other, and configured to rotate respectively about a first and a second axis of rotation, the first drum (40') and the second drum (40'') comprising, according to their respective axes of rotation, a proximal end connected to the cutting head (24), and a distal end (44', 44'') opposite the proximal end, in which: - said first drum (40') comprises, at its distal end (44'), a first cutting disc (50') or a first mounting means configured to allow the mounting of a first cutting disc, - said second drum (40'') comprises, at its distal end (44''),a second cutting disc (50") or a second mounting means configured to allow the mounting of a second cutting disc, wherein the first (50") and second (50") cutting discs are positioned substantially in the same plane, or the first and second mounting means are configured to position the first and second cutting discs substantially in the same plane. The invention also relates to a cutting disc for such an excavation machine, as well as a corresponding cutting method. Figure for the abstract: Fig. 5,

Description

Title of the invention: Excavation machine comprising cutting discs and corresponding cutting method Technical field

[0001] The present invention relates to the field of soil excavation and cutting machines, with rotary cutters, allowing in particular the creation of molded walls in the ground. Prior art

[0002] To make such diaphragm walls, it is first necessary to dig a trench whose geometry corresponds to the wall to be made. Then, the trench is filled with a grout or concrete, possibly provided with reinforcements, to obtain the diaphragm wall.

[0003] When the wall has a certain depth and it must be carried out with great precision, excavation machines of the hydrofraise type are most often used in which the cutting head is equipped with two rotating assemblies provided with excavation tools. These tools, under the effect of vertical thrust, disintegrate the ground or rock, which produces large quantities of spoil. During the drilling operation, the trench is kept filled with drilling liquid. The drilling spoil present in the drilling liquid is then evacuated from the trench by pumping.

[0004] Referring to the attached figures 1 and 2, an example of an embodiment of an excavation machine of known type will be described.

[0005] In [Fig. 1], an excavation assembly 9 is shown, similar to that described in application FR 2 806 111 which comprises a carrier 10 provided with a boom 12. On the end 14 of the boom 12, pass support cables 16 at the end 18 of which the excavation machine 20 itself is mounted. This machine 20 comprises a vertical chassis 22 at the lower end of which a cutting head 24 is mounted. The cutting head is essentially constituted by two rotary cutting assemblies 26 and 28 with horizontal axes of rotation, XX' parallel to each other. Preferably, each rotary cutting assembly is constituted by two cutters or drums mounted symmetrically on the chassis.The excavation machine may also comprise, to allow the cuttings to be raised, a suction inlet 30 arranged at the lower end of the chassis between the two rotary cutting assemblies 26 and 28, a suction pipe 32 connecting the suction inlet 30 to a suction device 34, for example a pump, and a conduit 36 ​​which allows the drilling liquid containing the cuttings to be sucked up in order to evacuate it to a . recovery facility. On the surface, another pipeline is also planned to fill the trench with drilling fluid.

[0006] In known excavation machines, the cylindrical drums rotate inside a volume of mud consisting in the lower part of two half-cylinders created by the cutting made by the excavation tools mounted on the drums, this volume extending essentially to the lower edge of the chassis.

[0007] However, such excavation machines are not suitable for working in any soil. Thus, when digging certain trenches, the excavation machine may encounter foreign bodies, in particular cables or tie rods, which may block the cutting head by wrapping themselves around the rotating cutting assemblies, or even damage the cutting head, for example when cutting live tie rods.

[0008] When such foreign bodies are detected, or even previously located even before the work of the excavation machine, it is then planned to use other machines or systems intended to remove or neutralize the foreign bodies in question.

[0009] Such as the case, for example, of anchor cables, or tie rods, which may be present in the ground due to previous work and left in place subsequently. Such cables can complicate digging work by the excavation machines which will have to cut them in order to be able to dig. In particular, when the cable is cut, there may be a release of tension energy stored in the cable initially, and likely to damage the excavation machine. In addition, the cables may block or even damage the excavation machine, in particular the drums or possibly the suction system, for example by becoming wrapped around the drums of the cutting head.

[0010] In such situations, it is known to loosen and possibly remove such cables present in the ground, prior to drilling operations by the excavation machine. However, such operations on the cables can be complicated to carry out, without guaranteeing the absence of other unidentified or unlisted cables in the area.

[0011] There is a real need to be able to manage the presence of foreign bodies, such as cables, in the ground to be excavated, in order to allow normal and safe operation of an excavation machine equipped with rotating drums. Statement of the invention

[0012] The present invention aims to solve the various technical problems set out above. In particular, the present invention aims to propose an excavation machine for digging a trench in a ground which may contain foreign bodies. More specifically, the present invention aims to propose a machine excavation capable of cutting cables or tie rods present in the ground, when digging the trench.

[0013] Thus, according to one aspect, there is provided an excavation machine comprising: - a vertical frame having a lower end; - a cutting head mounted at said lower end of the chassis, said cutting head comprising a first drum and a second drum positioned side by side, close to each other, and configured to rotate respectively around a first and a second axis of rotation, the first drum and the second drum comprising, according to their respective axis of rotation, a proximal end connected to the cutting head, and a distal end opposite the proximal end.

[0014] Said first drum comprises, at its distal end, a first cutting disc or a first mounting means configured to allow the mounting of a first cutting disc. Said second drum comprises, at its distal end, a second cutting disc or a second mounting means configured to allow the mounting of a second cutting disc. Said first and second cutting discs respectively have a diameter greater than or equal to that of said first and second drum.

[0015] The first and second cutting discs are positioned substantially in the same plane, or the first and second mounting means are configured to position the first and second cutting discs substantially in the same plane.

[0016] Thus, the excavation machine comprises two cutting discs, or two mounting means for cutting discs, mounted in the same plane and side by side so as to allow, during the rotation of the two drums of the cutting head, to cut any cables or tie rods present in the ground and crossing the outline of the trench. More precisely, the excavation machine is designed to cut the cables or tie rods when they come to position themselves between said two cutting discs. The excavation machine can thus neutralize cables or tie rods present in the ground, then carry out the usual ground digging operations, without requiring a change of machine.In order to cut the cables or tie rods, simply position the cable or tie rod between the two cutting discs, for example by rotating the drums so that their lower ends come closer to each other, then rotate the two drums, preferably in the opposite direction, until the cable or tie rod is cut.

[0017] Preferably, the cutting head also comprises a third drum and a fourth drum positioned side by side, close to each other, and configured to rotate respectively around the first and second axes of rotation, the third drum and the fourth drum comprising, along their axis of rotation respective, a proximal end connected to the cutting head, and a distal end opposite the proximal end.

[0018] Said third drum comprises, at its distal end, a third cutting disc or a third mounting means configured to allow the mounting of a third cutting disc. Said fourth drum comprises, at its distal end, a fourth cutting disc or a fourth mounting means configured to allow the mounting of a fourth cutting disc. Said third and fourth cutting discs respectively have a diameter greater than or equal to that of said third and fourth drum.

[0019] The third and fourth cutting discs are positioned substantially in the same plane, or the third and fourth mounting means are configured to position the third and fourth cutting discs substantially in the same plane.

[0020] Conventionally, excavation machines comprise two rotary cutting assemblies each comprising two drums driven in rotation around the same axis of rotation, generally horizontal, and extending substantially over the entire width of the trench to be dug, on either side of the vertical chassis of the excavation machine. Thus, with such an excavation machine with four drums, it becomes possible to cut only the part of the cable or tie rod extending into the volume of the trench to be dug: the cutting discs extending at the distal ends of the drums, that is to say along the end walls, or sides, of the trench, they can cut the cables or tie rods at the interface with the trench so as to allow the complete removal of the portion crossing the trench.

[0021] Furthermore, the drums being mounted along the same axis of rotation, two by two, the two ends of a portion of cable or tie rod can be cut at the same time, since each pair of cutting discs can come and cut, simultaneously, each end of the portion of cable or tie rod.

[0022] Preferably, the excavation machine also comprises at least one suction inlet fixed to the cutting head between the first and second drums, and a suction device connected to the suction inlet for removing the spoil excavated by the first and second drums.

[0023] The suction mouth allows the cuttings formed by digging the trench to be extracted from the trench, in particular the excavated soil but not the portions of cable or tie rod cut by the cutting discs. These cuttings are thus conveyed outside the trench, by suction with the drilling liquid circulating at the level of the cutting head. The suction mouth is positioned between the two drums, so as to facilitate the carrying of the cuttings towards them by said drums when they rotate in the direction shown in [Fig.2], that is to say when the tools excavation, or teeth, of these describe an upward movement at the central plane of symmetry of the cutting head.

[0024] According to a first embodiment, said first and second drums comprise said first and second mounting means, and said first and second mounting means each comprise: a bearing surface for the cutting disc, for example circular or crown-shaped, and means for fixing the cutting disc, for example tapped holes.

[0025] In this first embodiment, the cutting discs are removably mounted on the drums of the cutting head. Thus, the drums comprise mounting means on which the cutting discs can be mounted, or not, depending on the presence, or not, of cables or tie rods in the trench to be dug. The mounting means are configured to allow efficient and reliable mounting of the cutting discs at the distal end of the drums. To this end, the mounting means may comprise on the one hand fixing means, for example tapped holes, allowing screws to be tightened therein for fixing the cutting disc to the mounting means; and on the other hand a bearing surface, for example in the form of a disc or crown, on which the cutting disc will come to bear. The mounting means are thus designed to facilitate the mounting of the cutting disc, but also the maintenance, in use, of the cutting disc on the drum.

[0026] Preferably, the support surface also comprises openings configured to allow access to means for attaching the drum to the cutting head.

[0027] The bearing surface is configured to leave one or more sight glasses, for example openings, allowing access to the proximal end of the drum at which the latter is mounted on the cutting head. The sight glass, or opening, thus allows the drum to be mounted or dismounted from the cutting head, passing through said sight glass.

[0028] Preferably, the excavation machine also comprises a first cutting disc mounted on said first drum and a second cutting disc mounted on said second drum.

[0029] The invention therefore also relates to the excavation machine comprising mounting means and a cutting disc mounted on each of the mounting means.

[0030] Preferably, the first and second cutting discs comprise, on their peripheral periphery, a cutting material, preferably tungsten carbide or diamond powder.

[0031] The cutting discs are designed to allow efficient cutting while ensuring high mechanical strength. For this purpose, the cutting discs are provided with a diameter greater than that of the drums, or even greater than that of the drums with teeth: it is then possible to obtain a reduced inter-disc distance, and in particular less than the diameter of the cables or tie rods to be cut. Furthermore, the edges of the cutting discs are provided with materials having high mechanical resistance, in particular high hardness. Thus, the cutting discs can contain tungsten carbide, diamond powder or any other material suitable for such use. When cutting, the direction of rotation of the drums is preferably reversed compared to that used when digging the trench, that is to say the periphery of the drums describes a downward movement at the central plane of symmetry of the cutting head.The cables or tie rods are thus subjected to the simultaneous action of the edges of the two cutting discs which, on the one hand, come to bear on the cable or tie rod, under the effect of gravity, and on the other hand exert a downward constraint under the effect of the direction of rotation of the discs. Furthermore, such rotation of the drums also makes it possible to move the cut section of cable or tie rod away from the suction inlet: this limits the risks of damage or blockage at the level of the suction of the excavation machine. On the other hand, in the case of a cutting head without a suction inlet, it is possible to permanently maintain the same direction of rotation of the drums, whether during the digging phases or during the cutting phases.

[0032] Preferably, the first and second cutting discs also comprise first and second gripping means, for example openings, configured to cooperate with lifting means, and / or comprise first and second openings, preferably chamfered, for attachment to the first and second mounting means.

[0033] In order to facilitate the handling of the cutting discs and limit the risks of injury, in particular during the assembly and disassembly phases on the drum mounting means, the cutting discs may include gripping means, for example openings, to cooperate with lifting means, for example hooks. Similarly, the cutting discs may also include chamfered openings for fixing them to the mounting means using screws. In particular, the chamfers make it possible to protect the screw heads when using the cutting discs in the trench.

[0034] Preferably, the first and second cutting discs are positioned substantially in the same plane with a radial spacing less than or equal to 30 mm, preferably less than or equal to 10 mm, and more preferably less than or equal to 5 mm.

[0035] The space between the two discs mounted on two drums side by side, or adjacent, is chosen to be small to obtain as complete a cut as possible of the cable or tie rod, the free space between the two adjacent discs defining the residual size of the cable or tie rod likely to pass between the two cutting discs.

[0036] According to another aspect, there is also provided a cutting disc configured to be mounted on the mounting means of a drum of an excavation machine comprising said first and second mounting means, as previously described.

[0037] The invention also relates to the cutting disc as such, intended to be mounted on the drum of an excavation machine, with a view to cutting foreign bodies present in a soil to be dug.

[0038] According to a second embodiment, said first and second drums comprise said first and second cutting discs, and the first and second cutting discs comprise, on their peripheral periphery, a cutting material, preferably tungsten carbide, or diamond powder and / or openings configured to allow access to means for attaching the drum to the cutting head.

[0039] In this second embodiment, the drums directly include the cutting discs at their distal end: the cutting discs are therefore not mounted and dismounted on the drums according to the needs of the site, but it is the drums equipped with the cutting discs, or the cutting head with such drums, which are mounted or dismounted on the excavation machine according to the needs of the site.

[0040] Preferably, the first and second cutting discs are positioned substantially in the same plane with a radial spacing less than or equal to 30 mm, preferably less than or equal to 10 mm, and more preferably less than or equal to 5 mm.

[0041] As for the first embodiment, the distance between the cutting discs of the excavation machine according to the second embodiment is chosen to be small, to cut a maximum section of cable or tie rod, and to limit the residual size of these which could pass between the two cutting discs.

[0042] According to another aspect, there is also provided a method of cutting a metal element, for example a cable, with an excavation machine according to the first embodiment with cutting discs mounted on the mounting means or according to the second embodiment, in which the drums are rotated in opposite directions, with their lower ends moving away from or towards each other, and the cutting head is translated downwards when it is positioned above the metal element to be cut.

[0043] As previously indicated, the direction of rotation of the drums can be chosen so that their lower ends move away from each other. Such a direction of rotation may in particular be opposite to that used during digging of the trench. Thus, during digging, the drums rotate so as to convey the spoil between the two drums, where the suction inlet is located for evacuating said spoil with the drilling liquid, while during cutting, the drums convey the spoil, and in particular the sections of cables or tie rods away from the suction inlet. It should also be noted that, prior to cutting, in particular when the cables or tie rods are not initially positioned in the axis of the gap separating the two drums, the drums can be rotated with their ends approaching each other, so as to position said cables or tie rods located in said gap separating the two drums, then, in the cutting phase, the drums can be rotated in the opposite direction of rotation, to carry out the cutting.Furthermore, in order to improve the cutting effect of the cutting discs' perimeter, the excavator also uses the weight of the cutting head to keep the cutting discs in contact with the cable or tie rod during the cutting operation.

[0044] Alternatively, the direction of rotation of the drums, during the phase of cutting the metal element, can be chosen so that their lower ends approach each other. Such a direction of rotation corresponds in particular to that used during the digging of the trench. Such a direction of rotation can in particular be used during the phase of cutting the metal element, when the cutting head is without a suction mouth: in such a case, there is no risk of the portion of the cut metal element becoming blocked or damaging the mouth or the suction system. The direction of rotation of the drums can then remain the same, whether during the phases of digging the trench or during the phases of cutting a metal element.

[0045] Thus, when the excavation machine according to the present invention is devoid of a suction mouth, the rotation of the drums can be done all the time in the same direction, with the lower ends moving towards each other, or in different directions during the digging phases and during the cutting phases. More precisely, in the digging phase, the drums can rotate so as to bring their lower ends closer to each other, in particular so as to position cables or tie rods in the gap separating the two drums, then, in the cutting phase, the drums can be driven in rotation in the same direction, or in the opposite direction, with their lower ends moving away from each other.

[0046] Preferably, with an excavation machine according to the first embodiment, the first and second cutting discs are fixed, possibly after having removed teeth from the drums, to the first and second means of mounting of two drums of the excavation machine, the first and second cutting discs extending substantially in the same plane.

[0047] In the first embodiment, the cutting discs are mounted on the mounting means prior to the cutting operations. In this case, it is indeed necessary to extract the excavation machine from the trench, in order to mount the cutting discs there, but it is not necessary to use another, separate machine to cut the tie rods or cables: the excavation machine can remain on site, and successively carry out the steps of digging, cutting and then digging again, which limits the operations to be carried out by the operators and therefore the time required to carry them out.

[0048] Finally, the teeth can be removed from the drums beforehand, in particular to prevent the cut section of cable or tie rod from becoming wound around them and blocked.

[0049] Preferably, with an excavation machine according to the second embodiment, the drums comprising the first and second cutting discs, or the cutting head comprising such drums, are fixed to the excavation machine, the first and second cutting discs extending substantially in the same plane.

[0050] In the second embodiment, the drums with cutting disc, or the corresponding cutting head, are mounted on the excavation machine prior to the cutting operations. In this case, it is indeed necessary to extract the excavation machine from the trench, in order to mount the drums with cutting disc, or the corresponding cutting head, but it is not necessary to use another, separate machine, to cut the tie rods or cables: the excavation machine can remain on site, and successively carry out the steps of digging, cutting and then digging again, which limits the operations to be carried out by the operators and therefore the time required to carry them out.

[0051] Preferably, the drums comprising a cutting disc may be without teeth. Brief description of the drawings

[0052] [Fig.l] [Fig.l], already described, represents an excavation assembly of known type;

[0053] [Fig.2] [Fig.2], already described, represents in more detail the cutting head of the excavation machine of [Fig.l];

[0054] [Fig.3] [Fig.3] is a schematic perspective view of a drum, or cutter, for an excavation machine according to a first embodiment of the invention;

[0055] [Fig.4] [Fig.4] is a schematic perspective view of a cutting disc for an excavation machine according to the first embodiment; and

[0056] [Fig.5] [Fig.5] is a schematic perspective view of a cutting head of a excavating machine according to the first embodiment of the invention with cutting discs, or according to a second embodiment. Description of the embodiments

[0057] Figures 3 and 4 show an example of a drum 40 and an example of a cutting disc 50 for an excavation machine according to the first embodiment of the invention.

[0058] The drum 40 comprises, in a conventional manner, a proximal end 42 extending substantially in a plane perpendicular to the axis of rotation of the drum 40, and a distal end 44 opposite the proximal end 42 and extending substantially in a plane parallel to that of the proximal end. The proximal 42 and distal 44 ends substantially delimit the width of the drum 40 in the direction of its axis of rotation. Thus, the axis of rotation of the drum 40 being intended to be substantially horizontal in use, the proximal 42 and distal 44 ends extend substantially vertically when the drum 40 is mounted and used on the cutting head 24.

[0059] In order to allow the drum 40 to be mounted and driven in rotation, the cutting head 24 comprises cooperation means (not shown) on which the drum 40 is mounted. More precisely, the drum 40 is mounted on the cutting head 24 by its proximal end 42, while the distal end 44 extends opposite the cutting head 24.

[0060] Furthermore, the drum 40 also comprises, along its periphery, excavation tools, for example teeth 46 mounted on gussets 48 provided with tooth holders, driven in rotation by the drum 40 and making it possible to dig the ground during excavation. The teeth 46 and the gussets 48 may extend in different digging planes which are, for example, perpendicular to the axis of rotation of the drum 40 and which are distributed over the width of the drum 40. Thus, in [Fig. 3], the gussets 48 and the teeth 46 are positioned along two parallel planes arranged respectively near the proximal 42 and distal 44 ends of the drum 40. The gussets 48 and the teeth 46 may form a crown extending along the entire periphery of the drum 40, or form only segments partially surrounding the drum 40. Such segments are then defined directly by the different gussets 48.In particular, the positions of the different segments formed by the gussets 48 on the periphery of the drum 40 can be chosen to be staggered between the different planes. digging, possibly with overlapping portions between the different staggered segments.

[0061] The teeth 46 of the distal end 44 therefore make it possible to dig at the level of the side wall of the trench made by the excavation machine, while the teeth located at the level of the proximal end 42 or between the proximal end 42 and the distal end 44 make it possible to dig inside the trench made by the excavation machine.

[0062] However, when digging certain trenches, the excavation machine may encounter foreign bodies, in particular cables or tie rods, which may block the cutting head 24 by winding around the rotating cutting assemblies, or even damage the cutting head 24, for example when cutting live tie rods.

[0063] Thus, in order to neutralize such foreign bodies, and continue the excavation of the trench, the excavation machine 20 according to the present invention may comprise two or more cutting discs 50 as shown in [Fig.4].

[0064] According to the first embodiment illustrated in [Fig. 3], the drum 40 may comprise mounting means 52 intended to allow the mounting of a cutting disc at the distal end 44 of the drum 40. The mounting means 52 may in particular comprise, on the one hand, fixing means 54 allowing the fixing of the cutting disc 50 on the distal end 44 of the drum 40. The fixing means 54 may, for example, be tapped holes intended to cooperate with fixing screws of the cutting disc 50.

[0065] In particular, the mounting means 52, and more particularly the fixing means 54, are configured to allow reversible mounting of the cutting disc 50 on the drum 40, that is to say that the cutting disc 50 is removable. Such an embodiment therefore makes it possible to use the cutting head 24 of the excavation machine 20 in a conventional manner during excavation work, and to improve it with cutting discs 50 when foreign bodies, in particular cables or tie rods, are present in the area to be excavated.

[0066] Furthermore, the mounting means 52 may also comprise a bearing surface 56. The bearing surface 56 is intended to form a stable support for the cutting disc 50, making it possible to absorb any forces or stresses that may be exerted at the interface between the drum 40 and the cutting disc 50 during use of the cutting head 24. The bearing surface 56 is mounted at the distal end 44 of the drum 40 and has an exposed surface intended to come into contact with the cutting disc 50 when the latter is mounted on the drum 40.

[0067] In the case illustrated in [Fig. 3], the bearing surface 56 has a general crown shape, and has an exposed surface, for contact with the cutting disc 50, larger than the cross-section of a drum without such a bearing surface. The bearing surface 56 is integral with the drum 40, for example is welded to the cross-section of the drum 40.

[0068] The crown shape of the bearing surface 56 allows free access to the interior volume of the drum 40 to be maintained, all around the axis of rotation. However, such a bearing surface 56 could limit access to the means for attaching the drum 40 to the cutting head 24 (at the proximal end 42 of the drum 40). Thus, the bearing surface 56 may comprise openings 58, in this case six in number, distributed around the periphery of the bearing surface and providing access to the means for attaching the drum 40 to the cutting head 24. Thus, to fix or remove the drum 40 from the cutting head 24, it is sufficient to remove the cutting disc 50 from the fixing means 52, then to access the means for attaching the drum 40 via the openings 58.

[0069] The drum 40 according to the first embodiment therefore has a geometry and a use very similar to those of traditional drums, with the exception of the mounting means 52 provided at the distal end 44 of the drum 40 and configured to allow the mounting of a cutting disc 50 at the distal end 44 of the drum 40. In particular, in the absence of foreign bodies in the trench to be excavated, the operations of attaching / removing the drum from the cutting head, and the operations of digging the trench remain identical to those already implemented with traditional drums.

[0070] [Fig.4] illustrates an example of a cutting disc 50. The cutting disc 50 illustrated in [Fig.4] is a removable cutting disc 50 used with a drum 40 according to the first embodiment.

[0071] The cutting disc 50 preferably has a general crown shape, that is to say a disc shape with a central hole. The central hole is intended to allow free access to the interior volume of the drum 40 on which it is mounted, all around the axis of rotation of said drum 40.

[0072] In order to mount the cutting disc 50 on the drum 40, the cutting disc 50 may comprise chamfered openings 60 in which fixing screws (not shown) may be mounted and then screwed into the fixing means 54 of the drum 40. The chamfer makes it possible in particular, when using the cutting discs 50 during excavation operations, to avoid wearing, or even breaking, the screw heads by friction on the wall of the trench being excavated.

[0073] Furthermore, in order to facilitate the handling of the cutting disc 50 when it is fixed or removed from the drum 40, gripping means 62, for example in the form of openings allowing a lifting hook to be inserted therein, are provided, preferably close to the peripheral periphery of the cutting disc 50.

[0074] Finally, the cutting disc 50 advantageously comprises a cutting material 64 over all or part of its periphery. The cutting disc 50 being intended to cut foreign bodies present in the ground, in particular cables or tie rods, the purpose of the cutting material is on the one hand to obtain a faster cutting of said foreign body, and on the other hand to limit the wear of the peripheral periphery of the cutting disc 50. For this purpose, the cutting material is advantageously chosen from materials having a high hardness, for example diamond dust, tungsten carbide or any other material suitable for such use.

[0075] [Fig. 5] illustrates a cutting head 24 with cutting discs according to the first embodiment. In particular, the cutting head 24 comprises drums, for example four drums 40', 40”, 40'”, 40”” mounted in pairs on the two horizontal rotation axes X-X', and cutting discs, for example four cutting discs 50', 50”, 50'”, 50”” associated respectively with each of the four drums 40', 40”, 40'”, 40””.

[0076] In the first embodiment, each drum 40', 40' ', 40' ' ', 40' ' ” of the excavating machine corresponds to the drum 40 illustrated in [Fig. 3], and each cutting disc 50', 50”, 50”', 50”” corresponds to the cutting disc 50 illustrated in [Fig. 4],

[0077] As can be seen, the cutting discs are arranged in pairs, in two parallel planes. Thus, the first and second cutting discs 50' and 50' ' are positioned substantially in the same plane which corresponds to the plane of the distal ends 44', 44” of the first and second drums 40', 40”, while the third and fourth cutting discs 50'” and 50”” are positioned substantially in the same plane which corresponds to the plane of the distal ends 44'”, 44”” of the third and fourth drums 40” ', 40” ”.

[0078] Thus associated, each pair of cutting discs makes it possible to cut foreign elements, in particular cables or tie rods, crossing the trench to be excavated by at least one of its side walls. In this case, the cutting head 24 is placed in the trench so as to position said foreign body between the two cutting discs of the same plane. The movement of each cutting disc thus makes it possible to cut said foreign body from two opposite sides, until the complete cut is obtained.

[0079] In order to obtain a rapid and complete cut, the cutting discs of the same pair (i.e. positioned in the same plane) are close to each other, for example separated by a distance of less than 30 mm, preferably less than 10 mm and more preferably less than 5 mm.

[0080] According to a second embodiment, each drum 40', 40”, 40” ', 40” ” comprises, at its distal end, a cutting disc 50', 50”, 50”', 50”” secured to said drum.

[0081] In this case, the cutting disc is no longer removable, and therefore no longer has openings for attachment 60. The drum no longer includes mounting means 52. On the other hand, openings for access to the means for attaching the drum to the cutting head may be provided in the cutting disc.

[0082] When implementing the excavation machine to cut the foreign body, in particular the cable or the tie rod, the cutting head 24 is configured to allow rotation of the drums, and therefore of the corresponding cutting discs, in the opposite direction to that used when digging the trench. More precisely, the cutting head 24 is configured to rotate the drums so that, at the narrowest point between the two cutting discs, the peripheral periphery descends, that is to say so that the lower end of the cutting discs rotate away from each other. Such a movement corresponds to a clockwise direction of rotation for the first cutting disc 50' and a counterclockwise direction of rotation for the second cutting disc 50”.

[0083] At the same time, the cutting head 24 can be translated downwards, i.e. towards the foreign body, or can simply exert pressure on the foreign body under the effect of its own weight. This increases the contact force between the foreign body and the cutting material of the cutting discs, thereby improving the wearing or cutting effect of the cutting material on the foreign body.

[0084] However, before rotating the drums as described above to perform the cutting, it is possible to rotate them in the opposite direction, so as to naturally position the foreign body in the gap separating the two discs, in particular when the foreign body is not initially positioned in the axis of said gap. Once the foreign body is positioned between the two cutting discs, the drums can then be rotated in the other direction, so as to perform the cutting of the foreign body.

[0085] In the case of a cutting head without a suction mouth, the drums can be rotated, during the phase of cutting the foreign body, in the same direction as during the digging phase, that is to say with the lower end of the cutting discs approaching each other. In this case, the direction of rotation of the drums remains the same throughout the operating time of the cutting head.

[0086] In addition, and prior to cutting the foreign body, it is also possible to provide for a withdrawal of the teeth 46 of the drums 40 of the cutting head 24. Indeed, and even if the cutting discs 50 extend radially beyond the teeth 46, the foreign body to be cut could nevertheless be drawn in by the teeth 46 and damage, or even block, the drum 40 by wrapping itself around it. In order to limit such a risk, the teeth 46 can be removed from the gussets 48 prior to cutting.

[0087] Thus, thanks to the drum and the cutting disc according to the present invention, it becomes possible to dig a trench containing foreign bodies, more safely and more quickly. The cutting discs in fact allow in situ and rapid cutting of foreign bodies present in the trench, without requiring the use of another machine and while limiting the risks of damage to the equipment used. In particular, the drums according to the present invention take advantage of the operation of the cutting head to allow efficient and complete cutting of any cables or tie rods extending through the trench.

Claims

Claims

1. Excavating machine (20) comprising: - a vertical chassis (22) having a lower end; - a cutting head (24) mounted at said lower end of the chassis (22), said cutting head (24) comprising a first drum (40') and a second drum (40”) positioned side by side, close to each other, and configured to rotate respectively about a first (X) and a second (X') axis of rotation, the first drum (40') and the second drum (40”) comprising, along their respective axis of rotation, a proximal end (42', 42”) connected to the cutting head (24), and a distal end (44', 44”) opposite the proximal end (42', 42”), the excavating machine (20) being characterized in that: - said first drum (40') comprises, at its distal end (44'), a first cutting disc (50') or a first mounting means (52) on which a first cutting disc (50') is mounted,- said second drum (40”) comprises, at its distal end (44”), a second cutting disc (50”) or a second mounting means (52) on which a second cutting disc (50”) is mounted, in which said first and second cutting discs (50', 50”) respectively have a diameter greater than or equal to that of said first and second drum (40', 40”), in which the first and second cutting discs (50', 50”) are positioned substantially in the same plane.,

2. Excavating machine (20) according to claim 1, wherein said first and second drums (40', 40”) comprise said first and second mounting means (52), and wherein said first and second mounting means (52) each comprise: a bearing surface (56) for the cutting disc, for example circular or crown-shaped, and fixing means (54) for the cutting disc, for example tapped holes.

3. Excavating machine (20) according to claim 2, wherein the bearing surface (56) also comprises openings (58) configured to allow access to means for attaching the drum (40) to the cutting head (24).

4. An excavating machine (20) according to any preceding claim, wherein said first and second drums (40', 40”) comprise said first and second mounting means (52), and wherein the first and second cutting discs (50', 50”) mounted on said mounting means (52) comprise, on their peripheral periphery, a cutting material (64), preferably tungsten carbide or diamond powder.

5. An excavating machine (20) according to one of the preceding claims, wherein said first and second drums (40', 40”) comprise said first and second mounting means (52), and wherein the first and second cutting discs (50', 50”) mounted on said mounting means (52) also comprise first and second gripping means (62), for example openings, configured to cooperate with lifting means, and / or comprise first and second openings (60), preferably chamfered, for attachment to the first and second mounting means (52).

6. An excavating machine (20) according to any preceding claim, wherein said first and second drums (40', 40”) comprise said first and second mounting means (52), and wherein the first and second cutting discs (50', 50”) mounted on said mounting means (52) are positioned substantially in the same plane with a radial spacing of less than or equal to 30mm, preferably less than or equal to 10mm, and more preferably less than or equal to 5mm.

7. An excavating machine (20) according to claim 1, wherein said first and second drums (40', 40”) comprise said first and second cutting discs (50', 50”), and wherein the first and second cutting discs (50', 50”) of said first and second drums (40', 40”) comprise, on their peripheral periphery, a cutting material (64), preferably tungsten carbide, or diamond powder and / or openings configured to allow access to means for attaching the drum to the cutting head.

8. An excavating machine (20) according to claim 1 or 7, wherein said first and second drums (40', 40”) comprise said first and second cutting discs (50', 50”), and in in which the first and second cutting discs of said first and second drums (40', 40”) are positioned substantially in the same plane with a radial spacing less than or equal to 30mm, preferably less than or equal to 10mm, and more preferably less than or equal to 5mm.

9. An excavating machine (20) according to any preceding claim, wherein the cutting head (24) also comprises a third drum (40”') and a fourth drum (40””) positioned side by side, close to each other, and configured to rotate respectively about the first and second axes of rotation, the third drum and the fourth drum having, along their respective axes of rotation, a proximal end (42'”, 42””) connected to the cutting head, and a distal end (44'”, 44””) opposite the proximal end;the excavation machine being characterized in that: - said third drum (40”') comprises, at its distal end, a third cutting disc (50”') or a third mounting means (52) on which a third cutting disc (50'”) is mounted, - said fourth drum (40””) comprises, at its distal end, a fourth cutting disc (50””) or a fourth mounting means (52) on which a fourth cutting disc (50””) is mounted, in which said third and fourth cutting discs (50'”, 50””) respectively have a diameter greater than or equal to that of said third and fourth drum (40' ' ', 40' ' ”), and in which the third and fourth cutting discs are positioned substantially in the same plane.;

10. An excavating machine (20) according to any preceding claim, also comprising at least one suction inlet (30) attached to the cutting head between the first and second drums (40', 40”), and a suction device (34) connected to the suction inlet for removing spoil excavated by the first and second drums.

11. A method of cutting a metal element, for example a cable, with an excavating machine (20) according to any one of the preceding claims, wherein the drums (40', 40”) are rotated in opposite directions, with their lower ends moving away from or towards each other and the cutting head (24) is translated downwards when it is positioned above the metal element to be cut.

12. Cutting method according to the preceding claim in which said first and second drums (40', 40”) of said excavation machine comprise said first and second mounting means (52), and in which the first and second cutting discs (50', 50”) are fixed, possibly after having removed teeth (46) from the drums, on the first and second mounting means of two drums of the excavation machine, the first and second cutting discs extending substantially in the same plane.

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