FR2877538A1 - Self-propelled or towed agricultural machine e.g. sprayer, for spreading e.g. manure, has front axle coupled to frame through jack comprising chambers to which oil is provided so that attitude of frame is adjusted with respect to ground - Google Patents

Abstract

The machine has a frame (1) mounted on front and rear axles (8, 9) that are connected to the frame using oscillating links. The front axle is coupled to the frame through a jack (12) whose cylinder is articulated on the axle (8) and rod is articulated on the frame. The jack has chambers (12a, 12b) to which oil is provided from a hydraulic pump using a distributor so that attitude of the frame is adjusted with respect to ground.

Description

The present invention relates to agricultural machinery whose chassis is

  mounted in particular on at least one oscillating axle.

  More particularly, the invention relates to machines of this type, intended for spreading in the fields of fertilizer or phytosanitary products, commonly known as "sprayers", the invention being particularly applicable to such sprayers when they are equipped. their own propulsion system, that is to say when they are self-propelled.

  A major problem in the construction of such a machine is that of its stability when, while moving on the ground, it encounters irregularities of the ground (passages of the machine on furrows, pebbles etc.) that can harm not only to this stability, but also to the comfort of its driver.

  To this problem is added another, on the one hand, when the machine moves on a sloping ground, and on the other hand, when its course, in flat or sloping terrain, presents curves taken at a velocity such that centrifugal force influences stability.

  The two problems are particularly felt in the field of self-propelled sprayers, because these machines generally have a very high ground clearance and support a tank in which the treatment liquid to be spread in the fields is located.

  The center of gravity of these sprayers is therefore located very high (typically 2 or 3 meters above the ground) so that, without special precautions on the part of the driver, the machine may pour for example if we work in sloping fields, if the craft is traveling in a tight bend at a relatively high speed, or if the craft encounters significant irregularities in the terrain.

  This risk of overturning is increased by the liquid nature of the transported load, which moves downstream of the slope when the machine is located on a slope, and out of the curve when the machine takes a bend.

  The invention aims first of all to provide a self-propelled or trailed agricultural machine mounted in particular on at least one oscillating axle, having an improved ground contact regardless of the configuration and / or the slope of the ground, and to improve the stability of the ground. the craft in the curves.

  It should be noted that in the context of the present disclosure, the term free oscillating axle will designate an axle which is mounted on the chassis so as to be able to perform an unrestrained free rotation about an axis parallel to the direction of travel of the axle. machine. In addition, the expression axle oscillation controlled to an axle mounted on the frame will be affected so as to be able to rotate under the effect of a member such as a jack interposed between the axle in question and the chassis.

  The presence of oscillating links controlled or free axles to the chassis can then go with that of spring suspension devices, dampers and rackets usually provided to ensure the coupling of the chassis to the wheels of the vehicle. However, for reasons of simplification, the following will be abstracted from such suspension devices known per se and familiar to those skilled in the art.

  The invention therefore relates to an agricultural vehicle whose chassis is mounted in particular on at least a first oscillating axle, remarkable in that it comprises means for adjusting the inclination of said first axle relative to said frame.

  Thanks to these characteristics, the base of the chassis can be permanently corrected during the progression of the machine according to the configuration of the terrain so as to improve the support of the wheels on the ground and to allow adaptation to the superelevation. ground.

  According to other features of the invention: - said adjustment means are interposed between said frame and said axle, - said adjustment means are interposed between said frame and suspension means of said frame, - said adjustment means are interposed between means for suspending said chassis and said axle, - said adjusting means comprise at least a first double-acting cylinder, and means for controlling the first axle cylinder, - said control means comprise a manual hydraulic distributor. or automatic to selectively admit liquid into the chambers of said first axle jack, - said control means comprises an inclinometer sensitive to the inclination of said frame, a hydraulic distributor and a control device, preferably electronic, which in function of the signal provided by said inclinometer controls said hydraulic distributor so as to selectively delivering liquid to the chambers of said first axle cylinder, said agricultural machine comprises a second oscillating axle, said second axle is mounted free, said agricultural machine comprises means for adjusting the inclination of said second axle relative to said chassis. said adjustment means are interposed between said chassis and said second axle, said adjustment means are interposed between said chassis and suspension means of said chassis, said adjustment means are interposed between suspension means of said chassis and said second axle, - the means for adjusting the inclination of said second axle relative to said chassis comprise at least a second double-acting cylinder, and means for controlling said second axle cylinder, - said first and second axle cylinders connected to each other in closed hydraulic circuit filled with liquid in such a way that when one said cylinders is extended by a pivoting movement of its associated axle due to an unevenness of the ground, the other cylinder is actuated so as to rotate in the opposite direction its associated axle.

  Thanks to these features of the invention, uneven terrain acting on one of the axles will cause a change in the opposite direction of the inclination of the other axle relative to the chassis, so that in all circumstances the distribution of support of the machine on the ground will be ensured the best possible.

  According to other characteristics of the machine according to the invention: said first and second axle cylinders are mounted on the same side of said chassis, and their equivalent chambers are connected together, said first and second axle cylinders are mounted on opposite lateral sides of said chassis, and their equivalent chambers are cross-connected, the equivalent chambers of said first and second axle cylinders respectively associated with said first and second axles are connected in closed circuit filled with liquid, respectively to the chambers a control cylinder of said frame, also double-acting and controlled by control means, - said control means comprise a manual or automatic hydraulic distributor for selectively admitting liquid in the chambers of said cylinder of attitude control, - said control means comprise an inclinom is responsive to the inclination of said frame, a hydraulic distributor and a control device, preferably electronic, which according to the signal supplied by said inclinometer controls said hydraulic distributor so as to selectively admit liquid into the chambers of said control cylinder; plate, - said agricultural machine further comprises a tool suspended from said frame and which, during the work of the machine, is arranged generally transversely to the direction of progression of the machine and must then remain parallel to the slope of the ground , the orientation of this tool being modifiable by means of a motor member actuated according to the attitude of said frame so as to maintain the parallelism of the tool relative to the terrain slope, - said motor member comprises a corrector cylinder slave, there is provided a master correction jack fixed on said frame and connected chamber chamber closed circuit filled with liq uide said slave corrective cylinder, and there is provided means for adjusting said master correction cylinder according to the attitude of said frame, said adjustment means comprise a manual or automatic hydraulic distributor for selectively admit liquid into the chambers of said master correction jack, - means are provided for generating a pitch reference signal representative of the attitude of said chassis, and means for adjusting said master correction cylinder as a function of this setpoint signal, - said adjustment means comprise an inclinometer secured to said frame, said agricultural machine comprises motor means arranged for, via a preferably electronic control device, moving the rod of said master corrector cylinder according to the signal supplied by said inclinometer, said machine agricultural also includes manual means for controlling said correct cylinder slave and switching means for selectively connecting said slave corrective cylinder to said manual control means and to said master correction jack, said agricultural machine comprises means for adjusting said master correction jack according to the inclination between at least one said axles and said frame, - said adjusting means comprise at least one angle sensor placed at a location forming part of the group comprising the following locations: between said frame and said axle, between said frame and suspension means of this frame , and between suspension means of said chassis and said axle, - said master correction jack is placed at a location forming part of the group comprising the following locations: between said chassis and said axle, between said chassis and suspension means of this chassis , and between suspension means of said chassis and said axle, - said corrective cylinder master is connected in parallel and mechanically coupled to the control cylinder.

  The present invention also relates to an agricultural machine according to the foregoing, remarkable in that it is designed as a sprayer for spreading fertilizer and / or phytosanitary products in the field.

  Other features and advantages of the invention will become apparent from the following description given solely by way of example and with reference to the accompanying drawings, in which: FIG. 1 shows a diagrammatic side elevation view of a sprayer incorporating certain features of the invention; - Figure 2 is a schematic cross-sectional view of the sprayer of Figure 1, by two sections A-A and B-B, respectively front and rear, taken by the Y-Y and Y'-Y 'of its front and rear axles; FIGS. 3 and 4 show schematic views, similar to that of FIG. 2, of two other embodiments of the sprayer according to the invention; FIG. 5 shows, for another embodiment, a simplified diagram of the hydraulic circuit of the axle cylinders which are used in the embodiments of FIGS. 3 and 4 and to which is added a control cylinder of the chassis of the sprayer; - Figure 6 is a more detailed schematic front view of a sprayer according to the invention placed on a slope terrain; - Figure 7 shows a schematic cross-sectional view of the sprayer of Figure 6 taken by the axis of the rear axle; and FIGS. 8 and 9 show simplified diagrams of two embodiments of spray roll cant correction devices shown in FIGS. 6 and 7.

  In what follows, the invention will be described, by way of example only, in application to a sprayer for spreading on the ground liquid fertilizer and / or phytosanitary products.

  In certain applications of the invention, this machine can be designed as a self-propelled machine mounted on at least two axles each having at least two wheels, the application of the invention to this type of machine having many advantages taking into account the specificities such sprayers.

  However, it is expressly stated that the invention is not limited to this type of agricultural machinery. On the contrary, it can be implemented with advantage in all cases where an agricultural machine must move on a slope and / or irregular terrain, the machine is self-propelled or towed, has one or more axles or has a tool generally of significant length and oriented transversely to the direction of advancement of the machine, the inclination of the tool must then be adjusted to the best of the terrain.

  In this respect, the invention can be applied in particular to seeders having a seed drill with these general characteristics. Other examples of application are fertilizer spreading machines, microgranules, etc. That being said, FIG. 1 shows a sprayer comprising a frame 1 on which is mounted at the front AV as a working tool a spraybar 2 adjustable in height thanks to a deformable parallelogram 3 fixed to the frame 1 by a mount 4.

  The ramp is preferably deployable transversely to the direction of progression of the machine for spraying work and collapsible for road traffic. It should be noted, however, that the suspension mode of the ramp to the chassis of the machine is not limiting for the application of the present invention.

  Behind the frame 4 is installed a cabin 5 for the driver of the machine behind which is placed a tank 6 for containing the liquid product to be spread. At the rear AR, there is a powertrain 7.

  The sprayer which has just been briefly described to situate the characteristics of the invention is a non-limiting example of the many possible construction examples, particularly with regard to the locations on the chassis 1 of the main elements which have just been listed. .

  In the examples shown in the figures, the frame 1 is mounted on two axles 8 and 9, Y-Y axes and Y'-Y 'respectively carrying the wheels R1, R2 and R3, R4.

  These axles 8 and 9 are both connected to the frame 1 by oscillating links, respectively 10 and 11, shown very schematically in Figure 1 and allowing the pivoting of the two axles independently about a same longitudinal median axis X-X.

  It should be noted that, to simplify, the detailed structure of the suspension of the frame 1 on each axle has not been described or represented, such a suspension possibly comprising, for example, a triangular or square frame called "racket" by the specialists, connected with known manner to the chassis by springs and dampers.

  Figures 2 to 4 on which, for simplicity, the superstructures of the sprayer have been symbolized by simple rectangles show, by transverse sectional planes AA and BB visible in Figure 1, at least one of the two axles 8 and 9 is coupled to the frame 1 by a double-acting cylinder.

  In the example of Figure 2, the front axle 8 is a controlled oscillating axle because it is associated with a cylinder 12 whose cylinder is articulated on the axle and whose rod is hinged to the frame 1. The axle rear 9 is free oscillating and is associated with no cylinder.

  The chambers 12a and 12b of the jack 12 are connected to control means MC making it possible to vary their length. These control means may comprise a manual or automatic control device.

  In the first case, a distributor will make it possible, from a hydraulic pump, to admit oil into one or the other chamber of the jack 12 so that an operator can himself adjust the base of the cylinder. chassis 1 from the ground.

  In the other case, the adjustment of the attitude of the frame 1 can be obtained by making the control of the distributor dependent on an inclinometer (here not shown) placed on the chassis and acting on this distributor via a appropriate electronic circuit. Such adjustment means are known per se and do not have

  need a particular description.

  It will be understood that in the embodiment shown in FIG. 2, the attitude of the chassis 1 can be corrected at will by varying the length of the axle jack 12, and in particular so that this attitude remains substantially fixed by relative to the vector weight + centrifugal force when the sprayer is moving on a sloping terrain and / or when taking a sharp curve.

  In each of the embodiments shown in Figures 3 and 4, the two axles 8 and 9 are oscillating controlled, because they are each associated with a cylinder. These cylinders are placed and connected together hydraulically so that an inclination relative to the frame 1 of the axle with which it is associated generates on it, via the jack associated with the other axle, a force which tends to incline it in an opposite direction.

  Thus, referring first to FIG. 3, it can be seen that a jack 12 is articulated on the chassis 1 by its rod and on the axle 8 by its cylinder and that, on the same lateral side of the chassis 1, a cylinder 13 is articulated on the frame 1 by its rod and on the axle 9 by its cylinder.

  The cylinders 12 and 13 have chambers of the same volume and are interconnected by means of two pipes 14 and 15, the pipe 14 interconnecting the chambers 12a and 13a on the rod side and the pipe 15 connecting the chambers 12b and 13b together. piston side. Both cylinders and both lines are filled with oil.

  Therefore, when for example the axle 8 is inclined to the right due to the fact that the wheel R2 rolls on a stone in the field, the chamber 12a decreases in volume, thus driving the oil to the chamber 13a whose the volume increases.

  As a result, the length of the jack 12 decreases and the length of the jack 13 increases. Everything happens as if the axle 13 on which the stone has not yet acted, is pressed further to the ground.

  This provides a device for maintaining the ground support of the four wheels of the sprayer when it encounters a specific obstacle such as a pebble or a hole This support support contributes to maintaining the stability of the sprayer and limits the twisting forces imposed on the chassis.

  Note also that another advantage of this mode of mounting and connection of the cylinders is that the raising distance of a wheel of the front axle 8 on an obstacle of the ground (a stone for example) does not is reflected on the chassis 1 than half this distance, since the rear axle 9 acts in opposite directions vis-à-vis the chassis 1.

  If, then, this rear axle 9 will pass on the same obstacle, the chassis 1 will feel again a rise of only half the distance. Overall, the influence on the chassis of irregularities of the ground is smoothed.

  In this way, it is possible to reduce the forces imposed on the chassis, and considerably improve the comfort of the driver of the sprayer.

  The same effect is obtained if a jack of one of the axles is placed on the opposite lateral side of the chassis relative to the jack which is associated with the other axle, as shown in FIG. 4.

  In this case, a jack 16 is placed on the left lateral side of the frame 1, between the latter and the axle 8, while on the right side, there is a jack 17 interposed between the frame 1 and the axle 9.

  The chamber 16a on the rod side of the cylinder 16 is connected by a pipe 18 to the piston-side chamber 17b of the cylinder 17, while the piston-side chamber 16b is connected by a pipe 19 to the piston rod chamber 17a. It is advantageous to provide ducts 14, 15, 18, 19 of large section, typically 15 to 20 mm internal diameter.

  Those skilled in the art will appreciate that several other arrangements of axle cylinders are possible to achieve the same effect, placing them either on the same side or on two opposite sides and connecting the chambers together accordingly.

  One can for example consider placing two cylinders on each axle, respectively placed on either side of the articulation point of the axle relative to the chassis.

  It should be noted that the jacks 12, 13, 16, 17 can advantageously be thrust rod cylinders, that is to say comprising a rod extending on either side of the piston, and exiting through both ends of the cylinder.

  In such a cylinder, the cross sections of the two chambers located on either side of the piston are equal, and thus the chambers of two rods traversing rod can be connected indifferently to each other to obtain the operation described above.

  Figure 5 shows the hydraulic circuit of the cylinders 12 and 13 of Figure 3, the diagram being completed to illustrate another embodiment of the invention.

  This embodiment is in fact a combination on the one hand of the embodiment shown in FIG. 2, and on the other hand of one of the embodiments shown in FIGS. 3 and 4.

  A double-acting attitude control cylinder 20 is fixedly mounted on the chassis 1 by its cylinder, its rod 21 being coupled to control means MC.

  These may be of the same nature as that of the control means MC shown in Figure 2. The location of the cylinder 20 on the frame 1 may be chosen at any location thereof according to the construction facilities.

  The jack 20 is connected in closed circuit to the cylinders 12 and 13, namely by its rod-side chamber 20a to the rod-side chambers 12a and 13a of the cylinders 12 and 13 by two sections 14A, 14B of the pipe 14, and by its side chamber. piston 20b to the piston-side chambers 12b and 13b of the cylinders 12 and 13 by two sections 15A, 15B of the pipe 15.

  In this way, a displacement of the rod 21 of the attitude control cylinder 20 causes a displacement of the same magnitude of the pistons of the axle cylinders 12 and 13 which thus apply the same angle of inclination to each of the axles 8 and 9 relative to the chassis 1.

  It is therefore understood that by moving the rod 21, it is possible to act simultaneously and in the same direction on the two jacks 12 and 13, which makes it possible to very effectively correct the attitude of the frame 1, and in particular to so that this attitude remains substantially fixed with respect to the direction of the vector sum weight + centrifugal force when the sprayer moves on a sloping terrain and / or when he takes a curve at high speed.

  FIGS. 6 and 7 show a situation in which the frame 1 remains substantially horizontal in the presence of a slope angle α of the ground, by virtue of a device according to the embodiment of FIG. 2, or to the embodiment of Figure 5.

  It will be noted that actuating the axle cylinders 12, 13 with a plate control actuator 20 communicating chamber-to-chamber with them reduces their response time to a command sent by the control means MC relative to to a conventional hydraulic distributor system.

  It will also be noted that the operation proper to the embodiments of FIGS. 3 and 4 is not disturbed by the presence of the attitude control cylinder 20, and that it is therefore possible to cumulate the ground support function of the four wheels to the correction of the trim of the chassis.

  It will also be noted that the device of the embodiment of FIG. 5 could also be applied to a sprayer comprising two parts hinged together about a longitudinal axis, each part being provided with at least one axle bearing at least two wheels. .

  Another important feature of the invention, illustrated in greater detail in FIGS. 8 and 9, is more particularly applicable to agricultural machines having a tool which, during work, extends over a considerable length transversely to the direction of progression of the machine. the craft.

  In this case, the cant of the tool (a spray boom for example as shown) is adjustable for permanent maintenance parallel to the ground.

  For this purpose, it is known per se, as shown more particularly by way of example in FIG. 6, to suspend the ramp 2 to a link 30 itself articulated on the superstructure 31 of the chassis 1: it is commonly referred to as a suspension This rod 30 is coupled to the ramp 2 by a cylinder 32 for correcting the cant of the ramp, articulated on the two elements, said slave in what follows.

  Other suspensions of the ramp may be considered in the context of the present invention.

  The slave corrector cylinder 32 can be actuated in several ways, two preferred examples being shown in FIGS. 8 and 9.

  In FIG. 8, the chambers of the slave correction jack 32 can be connected to a pressure source 33 via a hydraulic distributor 34 through a double non-return valve 35.

  The distributor 34 is preferably placed on the dashboard of the machine so that the operator can manually adjust the slope of the ramp 2.

  A distributor 36 further allows, by the action on a control member 37 such as a pedal placed near the seat of the operator, to connect the chambers of the slave corrector cylinder 32 to the equivalent chambers of another correction jack 38, said master, whose displacement of the rod hydraulically translates the plate of the chassis 1.

  The master correction jack 38 is fixed by its cylinder to the frame 1 at any suitable place thereof and one of its chambers (here the rod-side chamber) can selectively be connected to a pressure accumulator 39 by the intermediate of a distributor 40 controlled by the control member 37 together with the distributor 36.

  The pressure accumulator 39 is isolated from the circuit when the system operates in automatic mode, that is to say when the master correction jack 38 communicates room-to-chamber with the slave correction jack 32.

  The cylinders 32 and 38 are connected to each other by pipes with a large section so as to allow a high flow rate of oil flow. As an indication, internal pipe diameters of 15 to 20 mm may be suitable.

  It is also seen that the rod of the master corrector cylinder 38 is articulated on a lever 41 which can pivot on the frame 1 and whose position is adjustable by means of an electric motor device 42 fixed to the frame also.

  The pivoting of the lever 41 is made as a function of the excursion of an inclinometer 43 placed on the frame 1 so as to measure the slope of the ground on which the machine is traveling, the motor device 42 being controlled by an electronic circuit 44. When the control member 37 is not actuated, the slope of the ramp

  2 can be set manually by the operator by means of the clapper 34.

  On the other hand, by pressing the pedal 37, the operator, through the distributor 36, communicates the two cylinders 32 and 38 chamber-to-chamber so that the adjustment of the slope of the ramp now proceeds automatically depending on the degree inclination of the chassis 1 measured by the inclinometer 43.

  In automatic mode, the slave corrector cylinder 32 copies the settings of the master correction jack 38, which thus makes it possible to directly correlate the slope of the ramp to the slope of the ground as measured by the inclinometer 43.

  The ramp 2 remains in this way substantially parallel to the ground on which the sprayer is traveling.

  During automatic operation, the accumulator 39 is isolated from the tilt correction control cylinder 38, ensuring, in manual mode only, the attenuation of pressure surges on the latter.

  Note that in the aforementioned case where the inclinometer 43 is mounted on the frame 1, the embodiment of Figure 8 can only function satisfactorily if the frame 1 is locked with respect to at least one of the two axles 8, 9, so that the information sent by the inclinometer 43 is directly representative of the slope of the terrain.

  If the frame 1 is locked against either of the two axles, it is possible to consider mounting the inclinometer on the frame, and use an average value of inclination measured by this inclinometer.

  Alternatively, it is conceivable to place the inclinometer directly on one of the axles, so as to collect information directly representative of the slope of the terrain, and ensure that there is no response to this information when the inclinometer jumps from an average position.

  This delay makes it possible to avoid a sudden correction of the slope of the ramp when the axle passes over a punctual obstacle.

  In the embodiment of FIG. 9, the master correction jack 38 is connected in the same way to the slave correction jack 32, but in this case it is interposed between one of the axles 8, 9 and the frame 1, next to of one of the axle cylinders 12, 13, 16 or 17.

  In this embodiment, in automatic mode, the slave corrector cylinder 32 copies the settings of the master correction jack 38, which thus makes it possible to incline the ramp 2 relative to the frame 1 by the same angle as that of the inclination of this chassis relative to the oscillating axle to which the master correction cylinder 38 is connected.

  It is thus possible to maintain the ramp 2 parallel to the ground, and whatever the attitude of the frame 1.

  Note that in the embodiment of Figure 9, it is preferable to place the master corrector cylinder 38 on the axle which is closest to the ramp 2, that is to say in this case on the front axle 8, as can be seen in FIG. 9.

  The hydraulic coupling of the slave corrector cylinder 32 with the master corrector cylinder 38 makes it possible to control the slope of the ramp 2 without saccades, and all the more so as the flow rate in the connection pipes can be high. The slope adjustment of the boom can thus be done smoothly.

  Of course, the present invention is not limited to the embodiments described and shown, provided by way of illustrative and non-limiting example.

  For example, one could envisage a self-propelled machine with three wheels, that is to say a wheel isolated on the one hand and two wheels mounted on an axle on the other hand, which would benefit from the precepts described above, namely whose axle would be oscillating and controlled so as to maintain the trim of the frame, and / or whose tool of great transverse length would be enslaved as indicated above.

  It is thus also that one could consider a more basic embodiment where the master correction jack 38 would be controlled by a hydraulic distributor.

  It is also possible that one could consider mounting this cylinder 38 in parallel with the control cylinder 20, and mechanically coupled thereto, instead of placing it between one of the oscillating axles and the chassis.

  Thus again it could be envisaged to control the master corrector cylinder 38 from the information sent by an angle sensor interposed between one of the oscillating axles and the chassis.

  It could further be envisaged to control the slave corrector cylinder 32 directly from said angle sensor.

  It will be noted that the invention which has just been described in the case of a self-propelled machine may also be transposed to a trailed implement, that is to say intended to be towed by a tractor by means of an articulated connection. such as a ball joint.

  It will also be noted that the invention covers situations in which the means (jacks or the like) for pivoting the oscillating axle (s) relative to the chassis are interposed between this chassis and suspension means (springs, dampers, triangular rackets). or rectangular) of this frame, or between these means of suspension and this (these axles).

Claims (34)

  Agricultural machine whose chassis (1) is mounted in particular on at least one first oscillating axle (8), characterized in that it comprises means for adjusting the inclination of said first axle (8) with respect to said chassis (1 ).   2. Agricultural machine according to claim 1, characterized in that said adjusting means are interposed between said frame (1) and said axle (8).   3. Agricultural machine according to claim 1, characterized in that said adjusting means are interposed between said frame (1) and suspension means of this frame.   4. Agricultural machine according to claim 1, characterized in that said adjusting means are interposed between suspension means of said frame (1) and said axle (8).   5. Agricultural machine according to one of claims 1 to 4, characterized in that said adjusting means comprise at least a first double-acting cylinder (12), and means (MC) for controlling the first axle cylinder.   Agricultural machine according to claim 5, characterized in that said control means (MC) comprise a manual or automatic hydraulic distributor for selectively admitting liquid into the chambers (12a, 12b) of said first axle cylinder. (12).   Agricultural machine according to claim 6, characterized in that said control means (MC) comprise an inclinometer responsive to the inclination of said frame (1), a hydraulic distributor and a control device, preferably electronic, which in function signal provided by said inclinometer controls said hydraulic distributor to selectively admit liquid into the chambers (12a, 12b) of said first axle cylinder (12).   Agricultural machine according to any one of the preceding claims, characterized in that it comprises a second oscillating axle (9).   Agricultural machine according to claim 8, characterized in that said second axle (9) is freely mounted.   10. Agricultural machine according to claim 8, characterized in that it comprises means for adjusting the inclination of said second axle (9) relative to said frame (1).   11. Agricultural machine according to claim 10, characterized in that said adjusting means are interposed between said frame (1) and said second axle (9).   12. Agricultural machine according to claim 10, characterized in that said adjusting means are interposed between said frame (1) and suspension means of this frame.   13. Agricultural machine according to claim 10, characterized in that said adjusting means are interposed between suspension means of said frame (1) and said second axle (9).   Agricultural machine according to one of claims 10 to 13, characterized in that the means for adjusting the inclination of said second axle (9) with respect to said frame (1) comprise at least a second double-acting cylinder (13, 17), and means for controlling the second axle cylinder (13, 17).   Agricultural machine according to claims 5 and 14, characterized in that said first and second axle cylinders (12, 13; 16, 17) are connected to each other in closed hydraulic circuit filled with liquid of such so that when one of said cylinders is extended by a pivoting movement of its associated axle due to an uneven ground, the other cylinder is actuated so as to rotate in opposite directions its associated axle.   16. Agricultural machine according to claim 15, characterized in that said first and second axle cylinders (12, 13) are mounted on the same side of said frame (1), and in that their equivalent chambers (12a, 13a 12b, 13b) are connected together.   Agricultural machine according to claim 15, characterized in that said first and second axle cylinders (16, 17) are mounted on opposite lateral sides of said frame (1), and in that their equivalent chambers (16a, 17a) 16b, 17b) are cross-connected.   18. Agricultural machine according to any one of claims 15 to 17, characterized in that the equivalent chambers (12a, 13a, 12b, 13b) of said first and second axle cylinders (12, 13) respectively associated with said first and second axles (8, 9) are connected in closed circuit filled with liquid, respectively to the chambers (20a, 20b) of a cylinder (20) of attitude control of said frame (1), also double-acting and controlled by means control (MC).   Agricultural machine according to claim 18, characterized in that said control means (MC) comprise a manual or automatic hydraulic distributor for selectively admitting liquid into the chambers of said attitude control cylinder (20).   20. Agricultural machine according to claim 19, characterized in that said control means (MC) comprise an inclinometer responsive to the inclination of said frame (1), a hydraulic distributor and a control device, preferably electronic, which in function signal provided by said inclinometer controls said hydraulic distributor to selectively admit liquid into the chambers (20a, 20b) of said attitude control cylinder (20).   21. Agricultural machine according to any one of the preceding claims, characterized in that it further comprises a tool (2) suspended from said frame (1) and which, during the work of the machine, is arranged generally transversely to the direction of progression of the machine and must then remain parallel to the slope of the ground, the orientation of this tool being modifiable by means of a motor member (32) actuated according to the plate of said frame (1) of in order to maintain the parallelism of the tool (2) with respect to the slope of the ground.   22. Agricultural machine according to claim 21, characterized in that said motor member comprises a slave correction jack (32), in that there is provided a master correction jack (38) fixed on said frame and connected room chamber circuit closed filled with liquid to said slave correction jack (32), and in that means are provided for adjusting said master correction jack (38) according to the attitude of said frame (1).   23. agricultural machine according to claim 22, characterized in that said adjusting means comprise a manual or automatic hydraulic distributor for selectively admit liquid into the chambers of said master correction jack (38).   24. Agricultural machine according to claim 22, characterized in that there is provided means for generating a slope reference signal representative of the attitude of said frame (1), and means for adjusting said master corrector cylinder (38). according to this setpoint signal.   25. Agricultural machine according to claim 24 when said frame is locked relative to at least one of said first and second axles (8, 9), characterized in that said adjusting means comprise an inclinometer (43) integral with said frame ( 1).   26. Agricultural machine according to claim 25, characterized in that it comprises motor means (41, 42) arranged for, via a control device (44) preferably electronic, move the rod of said corrector cylinder master (38) according to the signal provided by said inclinometer (43).   27. Agricultural machine according to claim 26, characterized in that it also comprises manual means (33, 34) for controlling said slave corrector cylinder (32) and switching means (36, 37, 39, 40) for selectively connecting said slave corrector cylinder (32) to said manual control means (33, 34) and said master corrector cylinder (38).   28. Agricultural machine according to claim 22, characterized in that it comprises means for adjusting said master correction jack (38) according to the inclination between at least one of said axles (8, 9) and said frame ( 1).   Agricultural machine according to claims 24 and 28, characterized in that said adjusting means comprise at least one angle sensor placed at a location forming part of the group comprising the following locations: between said frame (1) and said axle ( 8, 9), between said frame (1) and suspension means of this frame, and between suspension means of said frame (1) and said axle (8, 9).   30. Agricultural machine according to claim 28, characterized in that said master correction jack (38) is placed at a location forming part of the group comprising the following locations: between said frame (1) and said axle (8, 9), between said frame (1) and suspension means of this frame, and between suspension means of said frame (1) and said axle (8, 9).   31. Agricultural machine according to claim 22 when dependent on claim 18, characterized in that said master corrector cylinder (38) is connected in parallel and mechanically coupled to the control cylinder (20).   32. Agricultural machine according to any one of the preceding claims, characterized in that it is designed as a sprayer for spreading fertilizer and / or phytosanitary products in the field.   33. Agricultural machine according to claim 32, characterized in that it is self-propelled.   34. Agricultural machine according to claim 32, characterized in that it is trailed.