FR3120765A1 - Mowing/brush cutting device with optimized operation and associated method of operation - Google Patents

Abstract

The invention relates to a mowing/clearing device (1), comprising: - a rotor (21) driven in rotation about a transverse axis (11) and integral flails (22); - a cowling (3) covering an upper part and a rear part of the rotor (21) and forming an access opening (31) at the front of the rotor and (32) below the rotor, a volume (5) formed between the cowling and the rotor (21); -a control circuit (99) for controlling the drive of the rotor (21) so that the flails (22) have a negative speed according to a vector X at the level of the access opening (32) below the rotor ( 21); -a deflector (4) above the transverse axis (11) of the rotor, extending along the transverse axis (11) and positioned at a distance of between 5 and 30 mm from the circles (23) traversed by the free end of the flails (22) driven in rotation. Figure to be published with abstract: Fig. 4

Description

Mowing/brush cutting device with optimized operation and associated method of operation

The invention relates to mowing/clearing devices, frequently called mowers, and in particular mowers driven by a vehicle. Such mowing/clearing devices are intended to cut vegetation such as grasses, brushwood or reeds.

Cleaning the edges of the road is important to ensure the visibility of users, to promote the evacuation of rainwater or to limit the damage caused by vegetation on the road surface. For this purpose, operators most often use suitable motor vehicles, such as tractors equipped with a mower. The mower has an articulated arm attached to the vehicle chassis. A cutting tool is fixed at one end of the articulated arm. The cutting tool is generally in the form of a rotor driven in rotation by a hydraulic pump driven by the PTO of the tractor. Beams are secured to the rotor and distributed both angularly around the latter and longitudinally along its axis of rotation. In order to protect the public from any projectiles entrained during the operation of the mower, a cover covers the upper and rear parts of the rotor and the flails. The operation of the mower is controlled from the tractor cabin, a control circuit making it possible to control the inclination of the mower, its speed and its direction of rotation.

To illustrate the mowing of grass or reeds, an orthogonal marker can be defined with a direct orientation. The vector X corresponds to a longitudinal direction and to the direction of movement of the vehicle which will be considered as horizontal. The Z vector corresponds to a vertical direction and an upward direction. The vector Y has a transverse direction. Z is the cross product of vector X by vector Y.

For mowing grass or reeds, it is known to rotate the rotor of the mower in a negative direction, that is to say that the flails in the lower part move with a positive speed component according to the vector X, the flails in the upper part moving with a negative speed component according to the vector X. Such a rotation traditionally makes it possible to prevent the flow of air from flattening the grasses or reeds before they are mowed by the flails. Moreover, this direction of rotation tends to expel projectiles forwards with which the flails come into contact, for example pebbles. With a rotor rotation speed generally greater than 2000 rpm, the projection speed requires covering the front part of the mower with a protective cap to protect the public who may be present in the vicinity.

It has been observed that such a working method requires a reduced speed of movement of the vehicle, to allow good quality mowing and to avoid the risk of clogging by plants between the cap and the rotors. In addition, the presence of a protective cap does not facilitate good control of the mowing by the operator, the work area of the flails being hidden from the operator.

The invention aims to solve one or more of these drawbacks. The invention thus relates to a mowing/clearing device, comprising:
a rotor configured to be driven in rotation around a transverse axis having the direction and the sense of a vector Y;
-flails integral with the rotor;
-a cowling covering an upper part and a rear part of the rotor and forming an access opening at the front of the rotor and an access opening below the rotor, a volume being provided between the cowling and the upper part of the rotor so as to allow the passage of the beams between the cowling and the rotor, an advance vector X being perpendicular to the vector Y and having a direction going from the rear part of the rotor towards the access opening at the front of the rotor , a vertical vector Z having a direction going from the access opening below the rotor towards the upper part of the rotor, the mark (X, Y, Z) forming an orthogonal mark of direct orientation;
-a control circuit configured to control the drive of the rotor in rotation around the transverse axis, so that the flails driven in rotation have a negative speed according to the vector X when they are positioned at the level of the opening d access below the rotor;
-a deflector integral with the cowling and positioned above the transverse axis of the rotor, the deflector extending along the transverse axis and being positioned at a distance of between 5 and 30 mm from the circles traversed by the free end of the flails driven in rotation around the transverse axis.

The invention also relates to the following variants. Those skilled in the art will understand that each of the characteristics of the following variants can be combined independently with the characteristics above, without however constituting an intermediate generalization.

According to a variant, said flails are Y-flails.

According to yet another variant, the deflector is removably secured to the cowling.

According to another variant, the position of the deflector with respect to the cowling is adjustable to make it possible to modify said distance between the circles traversed by the free end of the beams and the deflector.

According to yet another variant, the device further comprises a motor capable of driving the rotor in rotation at a speed greater than 2000 rpm.

According to a variant, said deflector extends opposite all the beams.

According to yet another variant, the deflector is secured at several points distributed along the transverse axis.

According to another variant, the deflector is positioned at the level of the access opening at the front of the rotor.

The invention also relates to a vehicle, comprising:

-a mowing/clearing device as defined previously;

-a chassis ;

-a movable arm securing the mowing/brush cutting device to the frame.

Alternatively, the vehicle includes:

- a power take-off;

-a hydraulic pump driven by the power take-off, configured to drive said rotor in rotation.

Other characteristics and advantages of the invention will emerge clearly from the description which is given below, by way of indication and in no way limiting, with reference to the appended drawings, in which:

is a top view of an agricultural vehicle fitted with a mowing/clearing device according to the invention;

is a schematic cross-sectional side view of a mowing/brush-cutting device at rest according to the invention;

is a diagrammatic sectional side view of the mowing/clearing device of the in rotation ;

is a diagrammatic sectional side view of the mowing/clearing device of the mowing;

is a schematic cross-sectional view of an example of a mowing/clearing device fitted with a deflector;

is a schematic cross-sectional view of another example of a mowing/clearing device fitted with a deflector;

is a front sectional view of the attachment of flails to a rotor of a mowing/clearing device according to the invention;

is a perspective view of a mowing/clearing device according to the invention;

is a schematic cross-sectional view of another example of a mowing/clearing device fitted with a permanently mounted deflector;

is a schematic cross-sectional view of another example of a mowing/clearing device provided with a deflector having an anti-projection function.

There is a top view of an agricultural vehicle 9, fitted with a mowing/clearing device 1 according to an exemplary embodiment of the invention. The mowing/clearing device 1 according to the invention is further detailed below.

The agricultural vehicle 9 is here provided with a pilot cabin 90. A pilot circuit 99 is positioned at the level of the control station in the cabin 90. The pilot cabin 90 is fixed on a frame 92. The agricultural vehicle 9 comprises a power take-off 91. The mowing/brush-cutting device 1 according to the invention here comprises a hydraulic pump driven by the power take-off 91, configured to drive a rotor in rotation around a transverse axis 11. The rotor can be driven rotating by means other than a hydraulic pump. A motorization is for example capable of driving the rotor 21 in rotation at a speed greater than 2000 rpm, preferably at a rotation speed greater than 3000 rpm.

The mowing/brush cutting device 1 is here secured to the mobile arm 8.

The mowing/brush cutting device 1 is oriented so that the transverse axis 11 has the direction and the sense of a vector Y. The mowing/brush cutting device 1 has a horizontal direction perpendicular to the transverse axis 11, oriented along the direction and the direction of advance of the agricultural vehicle 9, corresponding to the vector X. The vertical direction and the direction from bottom to top corresponds to the vector Z. The mark (X, Y, Z) forms an orthogonal orientation mark direct

There is a schematic sectional side view of the mowing/brush cutting device 1 according to the invention at rest. The mowing/clearing device 1 comprises a cutting system 2. The cutting system 2 includes the rotor 21 and flails 22. The flails 22 are integral with the rotor 21, so that they can be driven in rotation with the rotor 21. The beams 22 are integral with the rotor 21 at one end and have another free end.

The mowing/clearing device 1 comprises a cowling 3 covering an upper part and a rear part of the rotor 21, in order to avoid the projections of objects which could be entrained by the rotor 21. The cowling 3 forms an access opening 31 at the front of the rotor 21 and an access opening 32 below the rotor 21. The access openings 31 and 32 allow access of vegetation to the flails 22. A volume 5 is provided between the cowling 3 and the upper part of the rotor 21 so as to allow the passage of the beams 22 between the cowling 3 and the rotor 21. The vector X has a direction going from the rear part of the rotor 21 towards the access opening 31 at the front of the rotor.

A deflector 4 is integral with the cowling 3. This deflector 4 is positioned above the transverse axis 11 of the rotor 21. The deflector 4 extends along the transverse axis 11 and is positioned at a distance between 5 and 30 mm of circles 23 traversed by the free end of the beams 22 driven in rotation around the transverse axis 11. The deflector 4 is here projecting inside the volume 5. These parameters are illustrated in illustrating the rotor 21 in rotation. The centrifugation of the beams 22 orients them in a radial direction with respect to the transverse axis 11. The dotted circle 23 corresponds to the trajectory of the free ends of the beams 22. The circles 23 make it possible to define the volume swept by the beams 22. The distance d corresponds to the distance between the circle 23 and the deflector 4.

The control circuit 99 is configured to control the drive of the rotor 21 in rotation around the transverse axis 11. According to this rotational drive, the beams 22 are driven in rotation to present a negative speed according to the vector X when they are positioned at the level of the access opening 32 below the rotor 21, and a positive speed according to the vector X when they are positioned in the volume 5 above the rotor 21. The speed of the flails 22 when they are at the level of the access opening 32 is illustrated in . The forward speed of vehicle 9 is also shown in .

Such a configuration makes it possible to limit the flow of air in the volume 5. The inventor has found that such a configuration proves to be particularly advantageous for mowing reeds with a high forward speed of the agricultural vehicle 9. By limiting air flow in volume 5, the reeds are prevented from being drawn around the rotor 21 in volume 5. Contrary to the a priori of those skilled in the art, this direction of rotation does not degrade the quality mowing the reeds and the implementation of the invention does not involve jamming reeds winding around the rotor 21. Contrary to another a priori of those skilled in the art, the limitation of the distance between the deflector 4 and the volume swept by the flails 22 does not increase the risk of jamming by rolling up the reeds and filling the volume 5.

An example of mowing reeds is shown in . The reeds are cut and driven under the rotor 21 and ejected towards the rear of the device 1.

For mowing reeds, it is possible to dispense with placing a protective cap to cover the access opening 31. The operator can then view the work of the mowing/brush-cutting device 1.

In the example of the , the deflector 4 is positioned at the level of the access opening 31, at the front of the rotor 21. This configuration proves to be advantageous in terms of maintenance and efficiency. It is also possible to envisage placing the deflector 4 inside the volume 5.

The inventor has also found that the use of Y-shaped flails limits the risk of the reeds being drawn into volume 5, in combination with deflector 4.

In order to facilitate the use of the mowing/clearing device 1 for other applications, and to allow for example not to interfere with a covering cap of the access opening 31, the deflector 4 is advantageously secured in such a way removable to the cowling 3. Such a removable attachment of the deflector 4 is for example made by bolting.

Advantageously, to enable the distance between the deflector 4 and the volume swept by the flails 22 to be finely adapted, the position of the deflector 4 relative to the cowling 3 is advantageously adjustable. The adjustment makes it possible, for example, to define a depth of projection of the deflector 4 in the volume 5, with respect to the cowling 3.

Figures 5 and 6 schematically illustrate two examples of adjustment of the distance between the deflector 4 and the volume swept by the beams 22.

In the example illustrated in Figures 5 and 6, the distance adjustment is achieved by sliding the deflector 4 in the volume 5.

In the example of the , the deflector 4 comprises a lip 42 intended to penetrate into the volume 5, at the level of the access opening 31. The deflector 4 also comprises an angle iron 41, oriented perpendicular to the lip 42. The angle iron 41 comprises a bore threaded. A screw 6 is rotatably mounted on the cowling 3 to form an endless screw. To this end, the cowling 3 has a bore through which a head 62 of the screw 6 passes. The head 62 of the screw 6 has two shoulders 63 and 64 positioned on either side of the cowling 3, in order to hold the screw 6 in position on the cowling in the direction X. The shoulder 63 is advantageously formed by a stress imprint, for example a hexagonal or square shape favoring drive by a screw key. The thread of the screw 6 is screwed into the threaded bore of the angle iron 41. Thus, when the screw 6 is driven in rotation, the screwing of the screw 6 into the thread of the angle iron 41 leads to a displacement of the lip 42 in direction X with respect to the beams 22.

Several adjustment mechanisms of this type may be provided. It is for example possible to position an adjustment by screwing at the level of each end of the cowling 3 in the transverse direction.

In the example of the , we take the structure of the . The threaded bore of the bracket 41 is replaced by a bore, the bore of the cowling is here replaced by a threaded bore. The screw 6 is here mounted to rotate on the angle 41, the shoulders 63 and 64 being positioned on either side of the deflector 4. The screw 6 is also screwed into the threaded bore of the cowling 3. Thus, when the screw 6 is driven in rotation, the screwing of screw 6 into the thread of cowling 3 results in a displacement of lip 42 in direction X with respect to flails 22.

One can also consider other types of adjustment, for example by pivoting a deflector with an eccentric relative to a pivot axis oriented along the vector Y.

In order to promote a reduction in the flow of air in the volume 5, the deflector 4 advantageously extends opposite all the flails 22, or in other words over the major part of the length of the rotor 21, or in other words over the entire length of the access opening 31.

As the access opening 31 can be relatively long, the deflector 4 can have a relatively long span and risks undergoing some bending. It is then possible to provide for fixing the deflector 4 at several points distributed along the transverse axis 11. It is also possible to envisage fixing the deflector 4 to the ends of the cowling 3 along the transverse axis, and to provide an intermediate contact between the deflector 4 and cowling 3.

There is a schematic sectional view of another example of a mowing/clearing device 1 provided with a permanently mounted deflector 4. Thus, the deflector 4 is here in the form of a section extending along the transverse axis. The profile is here positioned inside the volume 5. The profile is here fixed permanently on the cowling 3, by means of weld beads.

There is a schematic cross-sectional view of another example of a mowing/clearing device 1 provided with a deflector 4. Apart from the characteristics described below, the deflector 4 illustrated here is identical to that of the . The deflector 4 here has a protuberance 43 extending downwards. The protrusion 43 extends in the transverse direction. The protuberance 43 covers part of the access opening 31. The protrusion 43 provides additional protection against projections of objects despite the direction of rotation of the rotor 31, projections which may for example come from rebounds on the cowling 3. Thus , the deflector 4 can have both the function of preventing the entrainment of the vegetation in the volume 5, and a function of protecting the surroundings against projections.

Claims (10)

Mowing/clearing device (1), characterized in that it comprises:
-a rotor (21) configured to be driven in rotation around a transverse axis (11) having the direction and the sense of a vector Y;
-flails (22) secured to the rotor (21);
- a cowling (3) covering an upper part and a rear part of the rotor (21) and forming an access opening (31) at the front of the rotor and an access opening (32) below the rotor, a volume (5) being provided between the cowling and the upper part of the rotor (21) so as to allow the passage of the beams (22) between the cowling (3) and the rotor, an advance vector X being perpendicular to the vector Y and having a direction from the rear part of the rotor towards the access opening (31) at the front of the rotor, a vertical vector Z having a direction from the access opening (32) below the rotor towards the upper part of the rotor, the mark (X, Y, Z) forming an orthogonal mark of direct orientation;
-a control circuit (99) configured to control the driving of the rotor (21) in rotation around the transverse axis (11), so that the flails (22) driven in rotation have a negative speed according to the vector X when positioned at the access opening (32) below the rotor (21);
-a deflector (4) integral with the cowling (3) and positioned above the transverse axis (11) of the rotor, the deflector (4) extending along the transverse axis (11) and being positioned at a distance between 5 and 30 mm from the circles (23) traversed by the free end of the flails (22) driven in rotation around the transverse axis. A mowing/clearing device (1) according to claim 1, wherein said flails (22) are Y flails. Mowing/clearing device (1) according to Claim 1 or 2, in which the deflector (4) is removably secured to the cowling (3). Mowing/clearing device (1) according to any one of the preceding claims, in which the position of the deflector (4) with respect to the cowling (3) is adjustable to make it possible to modify the said distance between the circles (23) traveled by the free end of the flails and the deflector. Mowing/clearing device (1) according to any one of the preceding claims, further comprising a motor capable of driving the rotor (21) in rotation at a speed greater than 2000 rpm. Mowing/clearing device (1) according to any one of the preceding claims, in which the said deflector (4) extends opposite the set of flails. Mowing/clearing device (1) according to any one of the preceding claims, in which the deflector (4) is secured at several points distributed along the transverse axis (11). A mowing/clearing device (1) according to any preceding claim, wherein the deflector (4) is positioned at the level of the access opening (31) at the front of the rotor (21). Vehicle (9), characterized in that it comprises:
-a mowing/clearing device (1) according to any one of the preceding claims;
-a frame (92);
-a movable arm (8) securing the mowing/clearing device (1) to the frame (92). Vehicle (9) according to claim 9, comprising:
-a power take-off (91);
-a hydraulic pump driven by the power take-off (91), configured to drive said rotor (21) in rotation.