FR2820277A1 - ARTICULATED BRUSH TOOL HOLDER ARM - Google Patents

Abstract

The invention concerns an articulated arm (8) of a bush cutter fixed to a platform (49) integral with a tractor (9), consisting of an assembly of four manoeuvring devices (11, 12, 13, 14) and supporting a cutting tool (10) for mowing grass, cutting shrubs or pruning; the manoeuvring devices (11, 12, 13, 14) having a respective main direction (53, 62, 74, 75), consisting of a tubular structure comprising at one of their ends (57, 61, 69, 73) a motorised shaft perpendicular to the main direction (53, 62, 74, 75); each motorised shaft of the manoeuvring devices (11, 12, 13) enabling the pivoting of the manoeuvring device (11, 12, 13) to which it is secured; the manoeuvring device (14) enabling the pivoting of the cutting tool (10); said manoeuvring devices operating by means of a fluid at medium pressure while the cutting tool is generally powered by high pressure hydraulic fluid; the set of fluids circulating in the pipes within the manoeuvring devices.

Description

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 The invention relates to a brushcutting device mainly consisting of an articulated arm, the movements of which are ensured by integrated operating devices operating using low pressure fluids.

 We know the brushcutters that are attached to the rear of agricultural tractors; they are composed of an articulated arm at the end of which is attached a tool for mowing grass, brushcutting or pruning; the various segments of the arm are maneuvered by hydraulic cylinders operating under hydraulic pressure of the order of 150 bars to 300 bars. One of the major problems of these devices is the need to work under high hydraulic pressures on the one hand because of the bulk of the jacks which does not allow the use of large piston piston sections and on the other hand because of the importance of the efforts they must provide to operate the various elements of the structure of the brush cutter; these efforts cause problems with the rolling of the hydraulic fluid, generating sufficient heating to generate deteriorations in continuous operation detrimental to the reliability and safety of the process used to the point of calling into question the development of more powerful equipment which the market is demanding. . The movements between two segments of arms articulated between them are ensured by a jack which is the third side of a triangle whose length is variable; the variation in length of the third side varies the angle of the triangle which is opposite and which corresponds to the articulation of the two arm segments; the length ratio of a jack between the deployed position and the folded position being less than two, the maximum angle of movement of two segments of arms articulated between them remains relatively small and it is generally of the order of four- ninety degrees, which implies to improve the amplitudes of movements the use of complementary devices based on connecting rods which may also be the cause of malfunctions.

 Finally, the flexible pipes supplying pressurized hydraulic fluid to the hydraulic cylinders are in the open air and liable to be damaged by

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 arm movements and the risk of contact during operation with fixed obstacles.

 There is a component, capable of advantageously replacing hydraulic cylinders for certain applications and which consists in particular of a retractable tube which is flexible and liable to deform elastically; the retractable tube is made from a sheath, made of artificial textile fiber which is particularly resistant to breaking under tension, which is braided in a spiral and which is in particular coated with synthetic material making it impervious to fluids; when the shrink tube is put under a pressure of a few bars by any inflation fluid such as hydraulic oil, water or air, it has the particularity of increasing in diameter and shortening, by elastic deformation, thus keeping a substantially constant surface, while the volume increases slightly. When the shrink tube is retracted and it returns to its original volume; it evacuates inflation fluid, which has been previously injected, until it returns to its diameter and its initial volume; the inflation fluid is evacuated under pressure by restoring energy which can be reused so that overall the energy consumed remains low.

 The retractable tubes are associated with each other in a rigid tubular structure 7 (FIG. 1) of length significantly greater than the length of the retractable tubes used to constitute an operating device 1; the retractable tubes are fixed inside this tubular structure parallel to the main axis of the latter; they are supplied with inflation fluid at nominal pressure of the order of five to ten bars, from a compression device external to the tubular structure, by small supply pipes through sets of solenoid valves; after use, the outgoing fluid is returned by small return pipes, to the compression device under a residual pressure lower than the nominal pressure, to be re-pressurized there; the solenoid valves are controlled by an electronic control device receiving orders

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 by means of a control cable connected to a control device external to the tubular structure and supplied with electricity for the operation of the solenoid valves by an electrical operation cable. The tubular structure has first and second ends 2 and 3 located at the ends of the main axis 4; the first end 2 is closed by a compartment comprising in particular the electronic control device and the solenoid valves; the second end 3 is extended by a drive device 16 comprising a motorized shaft 5 whose pivot axis 6 is perpendicular to the main axis 4 of the tubular structure 1; this motorized shaft 5 is able on the one hand to pivot in one direction and in the other by a maximum angle, defined in advance by construction or adjustment, which can be greater than three hundred and sixty degrees and on the other hand develop a significant couple; the motorized shaft 5 comprises fixing means (not shown in FIG. 1) which can be based on the keying of splines or a circular clamping device.

 The object of the invention consists in adapting this operating device to make brushcutters attached to agricultural tractors which will not use jacks for their operation and therefore no high pressure hydraulic fluid; the use of inflation fluids at a pressure of five to ten bars considerably simplifies the hydraulic part; the large angle of rotation of the motorized shaft makes it possible to set up an articulated arm having a very simplified structure while allowing more complex movements; the use of electronics opens the door to simplifying the operating conditions for equipment.

 In the drawings.

 Figure 1 shows an operating device.

 FIG. 2 represents an overall perspective view of an articulated arm using a combination of segments made up in particular of operating devices according to the invention.

 Figure 3 shows in partial section an assembly of two operating devices to form a joint

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 with its fluid and energy supplies according to the invention.

 FIG. 4 represents a perspective view of a second end of an actuating element driving according to FIG. 3 before assembly.

 FIG. 5 represents a perspective view of a first end of an actuating element driven according to FIG. 3 before assembly.

 Figure 6 shows a perspective view of a detail of Figure 3 showing the mode of transfer of hydraulic fluid through the joint.

 Figure 7 shows a rear view of the tractor with the arm of Figure 2 folded.

 FIG. 8 shows a variant of the articulation of two operating devices.

 The invention consists in assembling several of these operating devices 11, 12, 13, 14 (fig. 2), which constitute arm segments, making it possible to obtain an articulated arm 8 (fig. 2), fixed on the one hand on a tractor 9 of the agricultural type and on the other hand to a cutting tool 10 used for mowing the grass, brush cutting or pruning; the assembly between them of two successive operating devices, which consists, for example, of an operating device 13 driving located on the side of the tractor and of an operating device 14 driven, is achieved by means of mechanical assembly and operation is ensured by means of transfer of inflation fluid and of fluid leaving from one operating device to the other, as well as by means of supply and electrical energy and electronic control means various operating devices 11 to 14 assembled; the articulated arm 8 must also include means for transferring the energy necessary for the operation of the cutting tool 10.

 The assembly between, for example, a driving device 17 (fig. 3) driving and a driving device 18 driven, hinged together, is done by adding, for example, at the first end 20 of the operating device 18 driven, a device 15 for fixing the tubular structure 21 of the operating device 18 driven on the motorized shaft 22 of the operating device 17

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 lively; the parameters defining the orientation and the position of the main axis 23 of the operating device 18 driven relative to the pivot axis 24 of the motorized shaft 22 are fixed for one piece of equipment, but can take, between different pieces of equipment , an infinity of values allowing a wide variety of movements of the operating device 18 driven; when the motorized shaft 23 pivots on itself, these movements can range from scanning by the main axis 23 of the operating device 18 driven by a plane parallel to the main axis 25 of the operating device 17 driving, to the rotation of the main axis 23, of the driven operating device 18, on itself perpendicular to the main axis 25 of the driving operating device 17 driving, passing through all the intermediate positions sweeping totally or partially conical surfaces or paraboloids hyperbolic of revolution. In practical terms, the motorized shaft 22 comprises, for example, grooves on which just fits a female grooved part, constituting a fixing device 15, integral with the first end 20 of the operating device 18 driven either directly or through a spacer; according to the needs, the fixing device 15 can be located at any other location of the tubular structure 21 as is explained below and oriented according to the needs as previously described.

 In a variant of the invention, especially when only a small clearance is required, the operating device 76 (FIG. 8) driving can have a motorized shaft 77 protruding on each side of the drive device 78; the driven operating device 79 comprises two fixing devices 80 and 81 which are fixed on each end of the motorized shaft 77, forming a stirrup, which makes it possible to intersect the main axes 82 and 83 of the operating device 79 driven and of the operating device 76 causing and eliminating the torsional forces.

 Protection against the external environment of the assembly of a driving actuating device and a driven operating device, constituting a

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 articulation can be achieved, for example, by a rubber bellows, a first end of which is fixed to the tubular structure of the second end of the driving device and a second end of which is fixed to the tubular structure of the first end of the driving device trained maneuver; this type of protection can be suitable in particular when the clearance is low as in the case of the double fluted motorized shaft previously described; but when the clearance is significant and the axes of the driving and driven operating devices form an acute angle it is no longer possible to use a bellows.

32 centré sur l'axe de pivotement 24 de l'arbre motorisé 22 ; le joint circulaire d'étanchéité 32 a de préférence un diamètre de l'ordre de grandeur de celui de la deuxième extrémité 30 et la partie du premier plan de joint 31 intérieure au joint circulaire d'étanchéité 32 est largement ouverte et constitue une ouverture centrale 33 le joint circulaire d'étanchéité 32 vient s'appliquer sur un deuxième In a preferred version of the invention, in the case where the drive device 17 (FIGS. 3 and 4) driving comprises a motorized shaft 22 located on one side of the drive device 26, it is associated with the device maneuver 17 driving a first bent tube 27 at ninety degrees having substantially the diameter of the tubular structure 28 of the operating device 17 having a first and a second end 29 and 30 whose axes of symmetry are intersecting and at right angles; the first end 29 of the bent tube 27 is, for example, fitted onto the tubular structure 28 by covering the second end 19 of the operating device 17 driving, so that its axis of symmetry coincides with the main axis 25 of the device maneuver 17 resulting; the dimensioning of the bent tube 27 is defined to cover the motorized shaft 22 and its drive device 26 so that the axis of symmetry of the second end 30 of the bent tube 27 is coincident with the pivot axis 24 of the motorized shaft 22; the second end 30 of the bent tube 27 has a first joint plane 31 perpendicular to the pivot axis 24 of the motorized shaft 22 which is equipped with a circular seal

32 centered on the pivot axis 24 of the motorized shaft 22; the circular seal 32 preferably has a diameter of the order of magnitude that of the second end 30 and the part of the first seal plane 31 inside the circular seal 32 is wide open and constitutes a central opening 33 the circular seal 32 is applied to a second

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plan de joint 34 (fig. 3 et 5) solidaire de la première extrémité 20 du dispositif de manoeuvre 18 entraîné centré sur l'axe du dispositif de fixation 15 venant se fixer sur l'arbre motorisé 22 comme précédemment décrit ; le deuxième plan de joint 34 qui se présente, par exemple, comme un disque avec un trou central 35 de diamètre inférieur à l'ouverture centrale 33 du premier plan de joint 31, est, par exemple, solidaire de la deuxième extrémité 36 d'un deuxième tube coudé 37 comportant une première extrémité 38 emboîtée sur la première extrémité 20 de la structure tubulaire 21 du dispositif de manoeuvre 18 entraîné. Les premier et deuxième tubes coudés 27 et 37 pivotent l'un par rapport à l'autre, suivant les premier et deuxième plans de joint 31 et 34, en constituant ce qui est appelé ci-après une articulation en préservant le dispositif d'entraînement 26 de l'arbre motorisé 22 des agressions climatiques. Dans une variante de l'invention les premiers et deuxièmes tubes coudés 27 et 37 sont équipés de trappes de visite 38 (fig. 2) dont la partie centrale est de préférence située au niveau de l'intersection dé l'axe de pivotement 24 (fig. 3) de l'arbre motorisé 22 avec la paroi des tubes coudés 27 et 37 ; ces trappes de visite 38 sont destinées notamment à faciliter le graissage ; dans une autre variante de l'invention le deuxième tube 37 coudé constitue le dispositif de fixation du dispositif de manoeuvre entraîné ; l'arbre motorisé comporte à son extrémité un disque de fixation, ayant sensiblement le diamètre de l'ouverture centrale du premier plan de joint et situé sensiblement dans son plan et qui est fixé, par exemple, par boulonnage, sur le disque formé par le deuxième plan de joint.

joint plane 34 (FIGS. 3 and 5) integral with the first end 20 of the operating device 18 driven centered on the axis of the fixing device 15 coming to be fixed on the motorized shaft 22 as previously described; the second joint plane 34 which is, for example, like a disc with a central hole 35 of diameter smaller than the central opening 33 of the first joint plane 31, is, for example, integral with the second end 36 of a second bent tube 37 having a first end 38 fitted on the first end 20 of the tubular structure 21 of the actuating device 18 driven. The first and second bent tubes 27 and 37 pivot relative to each other, along the first and second joint planes 31 and 34, constituting what is hereinafter called an articulation while preserving the drive device 26 of the motorized shaft 22 of climatic attacks. In a variant of the invention, the first and second bent tubes 27 and 37 are fitted with inspection hatches 38 (fig. 2), the central part of which is preferably located at the intersection of the pivot axis 24 ( Fig. 3) of the motorized shaft 22 with the wall of the bent tubes 27 and 37; these inspection hatches 38 are intended in particular to facilitate lubrication; in another variant of the invention the second bent tube 37 constitutes the device for fixing the driven operating device; the motorized shaft comprises at its end a fixing disc, having substantially the diameter of the central opening of the first joint plane and situated substantially in its plane and which is fixed, for example, by bolting, to the disc formed by the second parting line.

 The inflation fluid supply tubing and the inflation fluid supply tubing and the "return fluid outlet tubing are small section tubing operating at an average pressure of five to ten bars which convey a low flow rate; it is therefore easy to pass each of these two pipes inside the tubular structures of an actuating device 17 driving out of the second end 19 into the first bent tube 27 to pass into the second bent tube 37, by example passing freely through the opening

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 central 33 and, for example, passing through the disc of the second joint plane 34 passing through a protective sheath serving as an entry door into the operating device 18 driven; the distribution of inflation fluid and the collection of outgoing fluids in the various operating devices is done in parallel; the same is true for the electrical control cable and the control cables, which distribute the energy or the digitized information in parallel and follow a circuit similar to that of the pipes and the return of which is by mass.

 In another version of the invention, the inflation fluid tubing, the return fluid tubing, the electrical operating cable and the control cable or cables are grouped in a strand 39 (FIG. 3) which penetrates into the first bent tube 27 passing through the second end 19 of the drive device 17; a helical spring 40 surrounding the motorized shaft 22 has a first end 41 fixed relative to the operating device 17 driving and a second end 42 fixed relative to the driven operating device 18; the strand 39 emerging from the end 19 is fixed along the turns of the helical spring 40 going from the first end 41 to the second end 42 then, for example, crossing the disc of the second joint plane through an orifice 43 to then enter the operating device driven 18 by the first end 20.-Such a device allows to precisely control and minimize the stresses generated in the strand components during movements of the articulated arm.

d'énergie ; dans le cas où l'outil de coupe 10 utiliserait de l'huile hydraulique à une pression de l'ordre "de cent cinquante à trois cents bars et il est indispensable d'éviter au maximum de faire subir des mouvements de flexion importants. The cutting tool 10 (fig. 2) which is located at the end of the articulated arm 8 is generally a heavy consumer

of energy; in the case where the cutting tool 10 uses hydraulic oil at a pressure of the order of "one hundred and fifty to three hundred bars and it is essential to avoid as much as possible subjecting to significant bending movements.

 In a preferred version of the invention, the high pressure hydraulic fluid piping 44 (fig. 3 and fig 6) and the low pressure hydraulic fluid piping 46 pass internally through the tubular structure 28 of the operating device 17 driving and will be connected sure

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 a rotary joint 45 fixed to the end of the motorized shaft 22 which is opposite to that on which is fixed the fixing device 15 of the operating device 18 driven; the motorized shaft 22 is hollowed longitudinally from two concentric conduits and it is connected at the other end to the high and low pressure hydraulic fluid pipes 47 and 48, which pass through the driven operating device 18, which is fixed relative to the motorized shaft 22.

 In the case of an articulated arm comprising more than two operating devices placed end to end, the driven operating device becomes for the operating device following the driving operating device.

 It is possible to make articulated arms from different combinations of maneuvering devices to perform mowing, brushcutting and pruning functions which are assembled together as previously described while remaining in the field of invention.

 In a preferred version of the invention, this articulated arm 8 (fig. 2) is, for example, composed of four operating devices marked from 11 to 14; one end of which is fixed to a platform 49 at the rear of the tractor 9 and the other supports a cutting tool 10 which is positioned during operation, for example, on the right side of the tractor 9 taken from the direction of travel 54; during the description it is assumed that the wheel trains 50 and 51 of the tractor rest on a horizontal plane; the platform 49 comprises, on the one hand, a pump for recompressing the outgoing fluid (not shown in FIG. 2) for returning to the devices for operating the inflation fluid; and on the other hand, for example, a high pressure hydraulic pump (not shown in fig. 2) intended for driving the cutting tool in rotation, it furthermore comprises an electrical supply outlet and an outlet electronic control from the tractor cabin (not shown in fig. 2). A first operating device 11, which is a driving operating device having a length of the order of magnitude of the width of the tractor 9, is fixed horizontally, by a first fixing device 52,

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 on the platform with its main axis 53 oriented perpendicular to the direction of travel 54 of the tractor 9; the first end 55 of the first operating device It is placed on the right side of the tractor 9 it is closed, for example, by a cover 56 which fits onto the first end 55 of the first operating device 11; the second end 57 of the first operating device 11 comprises a first vertical motorized shaft turned upwards protected a first bent tube 58; the corresponding driven operating device, which is a second operating device 12 comprising a second horizontal motorized shaft, comprises a second fixing device enveloped by a second bent tube 59 forming with the first bent tube 58 a first articulation 60 situated in a plane horizontal; the second bent tube 59 takes a direction making an angle with the horizontal of the order of fifteen to twenty degrees and is connected, for example, directly to the first bent tube 61 of the second operating device 12, perpendicular to the main axis 62 of the latter and to the axis of rotation of the second motorized shaft, which is and remains horizontal during work; the first bent tube 61 of the second operating device 12, which has a length substantially equal to half the length of the first operating device 11, is capable of pivoting ninety degrees, towards the rear of the tractor 9 , from a position located in a vertical plane, containing the main axis 62 of the second operating device 12, perpendicular to the direction of movement 54 of the tractor 9 to a position located in a vertical plane parallel to the direction of movement 54 tractor 9; in a preferred version the second bent tube 59 and the first bent tube 61 constitute the fixing elements of the second operating device 12. The second motorized shaft of the second operating device 12 is connected to a fixing device integral with the first end 63 of a third operating device 13, the second operating device 12 comprises a first end 65 closed, for example, by a cover 64 as previously described and the second end closed with the first bent tube 61 whose first joint plane is

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 applied to the second joint plane of the second bent tube 66 of the third operating device 13 to form a second articulation 67; the third operating device 13, which has a length substantially equal to that of the first operating device 11, pivots around the second motorized shaft from a substantially horizontal position to a vertical position. The third operating device 13 has a second end 68 comprising a third motorized shaft which is horizontal oriented in the direction of travel 54 and protected by a first bent tube 69 on the first joint plane from which comes a second plane of application. joint of a second bent tube 70 of the fourth operating device 14 constituting a third articulation 71; the second bent tube 70 of the fourth operating device 14 comprises, from the second joint plane, a straight tubular part, the orientation of which is parallel to the pivot axis of the third motorized shaft of a length substantially less than the width of the tractor long enough to allow the tractor operator to easily see the cutting tool and short enough so that when the articulated arm 8 is folded back from the tractor 9 the cutting tool 10 does not exceed the width of the template tractor 9; this second bent tube 70 comes to fit on the first end 72 of the fourth operating device 14 which comprises a fourth horizontal motorized shaft and oriented in the direction of travel 54, located at its second end 73, on which is fixed the cutting tool 10 which pivots in a vertical plane along, for example, an angle of the order of one hundred and eighty degrees from a vertical position to an inverted vertical position passing through a horizontal position: this fourth device maneuver 14 can pivot from a position where its main axis makes a very closed acute angle with the main axis of the third maneuvering device when the articulated arm is folded up to, for example, a position where the main axes 74 and 75 of the third and fourth operating devices 13 and 14 are mutually parallel.

 The articulated arm 8 which has just been described is capable of folding back at the rear of the tractor 9 (fig. 7);

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 the second operating device 12 pivots around the first motorized shaft in order to be in a vertical plane parallel to the direction of movement of the tractor 9, so as not to exceed the gauge of the tractor 9 on its left side; the third and fourth maneuvering devices 13 and 14 are placed in a substantially vertical position by pivoting around the second and third motorized shafts and remain as has been previously specified inside the right side of the gauge of the tractor 9; the cutter tool 10 pivots around the fourth motorized shaft to take a position which, depending on its shape, also allows it to remain in the right side of the gauge of the tractor 9.

Claims (10)

 on the same side of a drive device (16, 26, 78) operating, by means of an inflation fluid supplied, from an outgoing fluid recompression pump, by an inflation fluid tube and which is brought back by a return fluid pipe, and thanks to electrical energy supplied by an electrical cable and controlled by a control cable, characterized in that the articulated arm (8) is produced by the articulation between them of operating devices , comprising a fixing device (15, 80, 81), of a driven operating device (18), which can be fixed, on the one hand, at any suitable place in the tubular structure (21) of the operating device ( 18) driven, on the other hand, on a motorized shaft (5,22, 77), of the operating device (17) driving, by means of mechanical assembly, while the inflation fluid, the return fluid , high and low pressure hydraulic fluids, electrical cables and control, circulate entirely inside the tubular structures of the successive operating devices, the passage from one operating device to the other of the fluids and cables being ensured by means of transfer (39, 40, 45) , protected by first bent tubes (27,58, 61, 69, 73) integral with the second end (19) of the operating devices (17) driving

 Claims 1-Articulated arm (8) fixed by one end to the rear of a tractor (9) of agricultural type having a direction of travel (54) and supporting at the other end a cutting tool for mowing the grass or for brushcutting or pruning, which is either electric or supplied with hydraulic fluid by a hydraulic pump via high pressure hydraulic pipes (44,47) and low pressure hydraulic pipes (46,48 ), capable of being folded back on itself at the rear of the tractor, using operating devices (1,11, 14,17, 18, 76, 79) made up of a tubular structure (7,21, 28 ), comprising a first end (2.20, 55, 65, 63, 72) and a second end (3.19, 57.68), a main axis (23, 25, 53.62, 74.82 , 83), the second end being equipped with a motorized shaft (5, 22,77) whose axis of rotation (5,24) is perpendicular to the main axis, pivoting on itself <Desc / Clms Page number 14>  and second bent tubes (37, 59, 66, 70) integral with the driven operating devices (18).  2-articulated arm according to claim 1, characterized in that the main axis (23) of the operating device (18) driven, relative to the pivot axis (24) of the motorized shaft (22) on which the driven operating device is fixed by a fixing device (15), can be oriented, according to the various equipment in an infinite number of directions from scanning, by the main axis (23), from a plane parallel to the main axis (25) of the operating device (17) causing the rotation of the main axis (23) on itself perpendicular to the main axis (25) passing through all the intermediate positions sweeping totally or partially conical surfaces or hyperbolic paraboloids of revolution.  3-articulated arm according to claim 1, characterized in that the drive device (76) driving has a motorized shaft (77) projecting on each side of the drive device (78), the drive device (79) having two fixing devices (80,81) which are fixed on each end of the motorized shaft (77) forming a stirrup.  4-articulated arm according to claim 1, characterized in that a first bent tube (27) at ninety degrees having a first and a second end (29,30), the first end (29) of the bent tube (27 ) being fitted onto the tubular structure (28), the second end (30) having a first joint plane (31), having a central opening (33), perpendicular to the pivot axis (24) which is equipped with a circular seal (32) coming to apply, to constitute a joint (60, 67, 71), on a second joint plane (34) integral with the second end (36) of a second bent tube ( 37) having a first end (38) integral with the tubular structure (21) of the driven operating device (18).  5-articulated arm according to claim 4, characterized <Desc / Clms Page number 15>  in that the first and second bent tubes (57, 58, 61, 66, 69, 70, 73) are equipped with inspection hatches (38).  6-articulated arm according to claims 1 and 4, characterized in that the second bent tube (37) constitutes the fixing device, of the actuating device (18) driven, on the motorized shaft which comprises at its end a disc of fixing, having substantially the diameter of the central opening (33) of the first joint plane (31) and situated substantially in its plane and which is fixed, on the disc formed by the second joint plane (34).  7-articulated arm according to claim 1, characterized in that the inflation fluid tubing, the fluid tubing of return the electrical operating cable and the control cable or cables are grouped in a strand (39) which is fixed the along a helical spring (40), surrounding the motorized shaft (22), a first end (41) of which is fixed relative to the drive device (17) driving and a second end (42) which is fixed relative to the device of maneuver (18) driven.  8-articulated arm according to claim 1, characterized in that the high pressure hydraulic fluid piping (44) and the low pressure hydraulic fluid piping (46) which have passed through the operating device (17) driving, are connected to a rotating joint (45) -fixed on one end of the motorized shaft (22) which is hollowed out longitudinally from two conduits and which is connected at the other end to the high and low pressure hydraulic fluid pipes (47,48), which pass through the driven operating device (18).  9-articulated arm according to claim 1, characterized in that it is composed of four operating devices (11,14), hinged together, one end of which is fixed on a platform (49) and the other end supports a cutting tool (10), the platform (49), comprising a recompression pump, a high pressure hydraulic pump, an electrical supply outlet and an electronic control outlet, supports a first operating device (11 ), having a first end (55) and a second end (57), which is fixed <Desc / Clms Page number 16>  horizontally with its main axis (53) oriented perpendicular to the direction of travel (54), the first end (55) being closed by a cover (56), the second end (57) comprising a first vertical motorized shaft turned upwards protected a first bent tube (58), the second operating device (12) comprising a second horizontal motorized shaft, comprises a second fixing device enveloped by a second bent tube (59) forming with the first bent tube (58) a first articulation (60), the second bent tube (59) taking a direction making with the horizontal an angle of the order of fifteen to twenty degrees and coming to be connected directly to the first bent tube (61) of the second operating device (12 ), perpendicular to the main axis (62) of the latter and to the axis of rotation of the second motorized shaft which is connected to a fixing device integral with the first end (63), of a t third operating device (13), comprising at its first end (63) a second bent tube (66) forming with the first bent tube (61) a second articulation (67), having a second end (68) comprising a third shaft motorized which is horizontal and protected by a first bent tube (69) forming a third articulation (71) with a second bent tube (70), of the fourth operating device (14), comprising from the second joint plane a tubular part rectilinear, the orientation of which is parallel to the pivot axis of the third motorized shaft, this second bent tube (70) fitting onto the first end (72) of the fourth operating device (14) which comprises a fourth shaft horizontal motorized, located at its second end (73), on which is fixed the cutting tool (10) which pivots in a vertical plane, 10-articulated arm according to claims 1,4, 6 and 9, characterized in that the second bent tube (59) and the first bent tube (61) constitute the second fixing device of the second operating device (12), the second bent tube (66) constitutes the third for fixing the third operating device (13), the second bent tube (70) constitutes the fourth device for fixing the fourth operating device (