Agricultural machinery with active hitch points

Abstract

The present invention relates to an agricultural machine comprising at least one working tool and a hitch frame by which it is connected to a tractor and which comprises a cross member and two levers, each lever carrying a respective trunnion intended to be attached to a respective lower arm of the tractor and capable of moving vertically relative to the cross member, each lever being associated with a return device capable of exerting a force on the associated lever when the respective trunnion moves vertically relative to the cross member, the machine being able to occupy a working configuration in which the or each tool is close to the surface and at least one transport configuration, in which the or each tool is further from the surface than in the working configuration, each return device comprises a hydraulic return cylinder fixed to the respective lever on one side and to the cross member on the other side,each return cylinder being hydraulically connected to a hydraulic reservoir in working configuration. Figure to be published with the abstract: Fig.1,

Description

Title of the invention: Agricultural machine with active hitching points

[0001] The present invention relates to the field of agricultural machinery and more particularly to an agricultural machine comprising at least one working tool and a hitching frame, by which it is connected to a tractor and which comprises a cross member and two levers, each lever carrying a respective trunnion intended to be attached to a respective lower arm of the tractor and capable of moving vertically relative to the cross member, each lever being associated with a return device capable of exerting a force on the associated lever, when the respective trunnion moves vertically relative to the cross member, the machine being able to occupy a working configuration in which the or each tool is close to the surface, and at least one transport configuration in which the or each tool is further from the surface than in the working configuration.

[0002] Such a machine is described in document EP 2 953 445 A1. In this document, the return device comprises elastically deformable elements making it possible to store and restore energy to the associated journal, when the latter moves vertically. Such return devices make it possible to reduce the risks of the machine tipping over in the transport configuration, by storing a force which they restore to the lever(s) to return it(them) to the initial position. In the working configuration of the machine, the elastically deformable elements of these return devices also transmit forces between the tractor and the machine, when a journal is moved vertically relative to the machine's coupling frame, which may imply a reduced service life for the tractor's coupling device and the machine's coupling frame.In addition, elastically deformable elements also imply a limited amplitude of the journal movements, inducing a limited adaptation of the machine to a bumpy surface, which can lead to a lower quality of work, but also deterioration of the tools and / or the surface.

[0003] The present invention aims to overcome at least some of the aforementioned drawbacks for such an agricultural machine.

[0004] For this purpose, each return device comprises a hydraulic return cylinder fixed to the respective lever on one side and to the cross member on the other, each return cylinder being hydraulically connected to a hydraulic reservoir in the working configuration.

[0005] Thanks to these arrangements, the movements of the machine relative to the tractor are freer in the working configuration, allowing better adaptation of the machine on a bumpy surface and advantageously reducing the constraints in the tractor's coupling device and in the machine's coupling frame.

[0006] The invention will be better understood from the following description, which relates to different preferred embodiments, given as non-limiting examples, and explained with reference to the appended schematic drawings, in which:

[0007] [Fig-1] represents a simplified top view of a machine according to a first variant of the invention, attached to the rear of a tractor, in which the coupling cylinders are hidden,

[0008] [Fig.2] represents a perspective view of a coupling according to the preferred embodiment of the invention,

[0009] [Fig.3] represents a side view of a machine according to a preferred variant of the invention, in working configuration,

[0010] [Fig.4] represents a simplified side view of the machine according to the preferred variant of the invention, in transport or maneuvering configuration,

[0011] [Fig.5] represents a diagram of the hydraulic circuit of the machine according to the preferred variant, the hydraulic circuit of the machine being connected to the hydraulic circuit of the tractor, and,

[0012] [Fig.6] shows a side sectional view of the hitch of [Fig.2], the location of the section being shown in [Fig.l].

[0013] As shown in [Fig.l], the agricultural machine (1) according to the invention comprises at least one tool (10). The machine (1) also comprises a hitching frame (4) by which it is connected to a tractor (3). The tractor (3) comprises two lower arms (8a, 8b). The tractor (3) is equipped with a hitching device comprising a left lower arm (8a) and a right lower arm (8b). The tractor (3) is able to move with or without the machine (1) in a main direction (D). The tractor (3) moves on a surface (S). This is the surface (S) of the ground on which the tractor (3) and the machine (1) move, preferably the surface (S) of a field when the machine (1) is at work. The tractor (3) also makes it possible to drive the machine (1), in particular thanks to its power take-off and / or its hydraulic circuit. A central plane (P) passes through the middle of the tractor (3). The central plane (P) is vertical.It is also parallel to the main direction (D). The central plane (P) is equidistant from the lower arms (8a, 8b).

[0014] In the present description, the notions front, rear, in front, behind, right and left are defined by looking in the main direction (D).

[0015] The machine (1) also comprises at least one beam (13). The beam (13) connects the at least one tool (10) to the hitch frame (4). Preferably, the beam (13) connects the at least one tool (10) to the hitch frame (4) by means of at least one drawbar (50). The hitch frame (4) is preferably located in front of the beam (13). Thus, the machine (1) is preferably coupled to the rear hitch device of the tractor (3). In an embodiment not shown, the machine (1) could however be coupled to the front tractor coupling device (3).

[0016] The machine (1) comprises a hydraulic circuit (40). The tractor (3) also comprises a hydraulic circuit (30). The hydraulic circuit (30) of the tractor (3) comprises at least one reservoir (33). The hydraulic circuit (30) of the tractor (3) also comprises a pump (31) and a hydraulic distributor (32). The hydraulic circuit (30) of the tractor (3), and in particular the pump (31) or the reservoir (33), may be connected to the hydraulic circuit (40) of the machine (1) via the distributor (32). The pump (31) makes it possible to send pressurized oil into the hydraulic circuits (30, 40). The pump (31), the reservoir (33) and / or the distributor (32) could also be part of the hydraulic circuit (40) of the machine (1).

[0017] The hitch frame (4) comprises a cross member (5) and two levers (6a, 6b). Each lever (6a, 6b) carries a respective trunnion (7a, 7b). Each trunnion (7a, 7b) is intended to be attached to a respective lower arm (8a, 8b) of the tractor (3). In this document, many parts are symmetrical with respect to the central plane (P). It is agreed to reference these symmetrical parts to the left of the central plane (P) by an a and those to the right by a b. Thus, it is agreed to reference a first lever, the left lever (6a), and a second lever the right lever (6b). In the same way, it is also agreed to name a first trunnion, the left trunnion (7a) and a second trunnion, the right trunnion (7b) .. .etc. Thus, the first journal (7a) is attached to the left lower arm (8a) of the tractor hitch (3) and the second journal (7b) is attached to the right lower arm (8b) of the tractor hitch (3).The vertical is orthogonal to the main direction (D) and to the line passing through the journals (7a, 7b).

[0018] So as to allow good adaptation of the machine (1) relative to the tractor (3) when they move on a bumpy surface (S), each journal (7a, 7b) can move vertically relative to the crossbar (5). In addition, each journal (7a, 7b) is articulated with the associated lever (6a, 6b) about a hitch axis (16a, 16b). Each hitch axis (16a, 16b) is horizontal. Each hitch axis (16a, 16b) is also perpendicular to the main direction (D).

[0019] As can be seen particularly from [Fig.2], a return device (9a, 9b) is associated with each lever (6a, 6b). Each return device (9a, 9b) can exert a force on the associated lever (6a, 6b) when the respective journal (7a, 7b) moves vertically relative to the crossbar (5).

[0020] In the first embodiment of [Fig.l], the tool (10) is attached to the rear end of the beam (13). In the preferred embodiment of [Fig.3], a rear tool (10) is attached to a rear beam (15). The front tool (10) is located in front of the rear tool (10). The rear beam (15) is connected to the beam (13) by a joint allowing at least one pivoting about a substantially vertical central axis (12). As shown in this [Fig.3], the machine (1) can occupy a working configuration, in which the or each tool (10) is close to the surface (S). As shown in [Fig.4], the machine (1) can also occupy a transport configuration, in which the or each tool (10) is further from the surface (S) than in the working configuration.

[0021] The machine (1) can preferably also occupy a maneuvering configuration, in which the or each tool (10) is also far from the surface (S). In the first variant of [Fig.l], the maneuvering and transport configurations are substantially identical. In the working configuration, the beam (13) is also closer to the surface (S) than in the transport and maneuvering configuration. The machine (1) rests on the surface (S) by means of rollers (14) and this regardless of the configuration (working, transport or maneuvering) of the machine (1). Preferably, each tool (10) is associated with at least two respective rollers (14). Preferably, the rollers (14) are oriented so that the beam (13) is substantially parallel to the main direction (D).

[0022] According to an important characteristic of the invention, each return device (9a, 9b) comprises a hydraulic return cylinder (11a, 11b). Each return cylinder (11a, 11b) is fixed to the respective lever (6a, 6b) on one side and to the crosspiece (5) on the other side. Respectively, each return cylinder (11a, 11b) is integral with the respective lever (6a, 6b) by its rod or its cylinder. Each return cylinder (11a, 11b) is also integral with the crosspiece (5) by that of its rod or its cylinder which is not integral with the respective lever (6a, 6b). In the working configuration, each return cylinder (11a, 11b) is hydraulically connected to a hydraulic reservoir (33). The return cylinders (11a, 11b) are said to be mounted floating. In this way, the extension of each return cylinder (11a, 11b) is free in working configuration.Thus, the movements of the machine (1) are freer in working configuration, improving its ability to adapt to a bumpy surface (S) and reducing the stresses in the hitch frame (4) and the tractor hitch device (3) when moving the machine (1) on a bumpy surface (S).

[0023] As can be seen from [Fig.4], the drawbar (50) and a rod (51) are each articulated with the beam (13) along a respective horizontal axis. An adapter (52) is articulated with at least the drawbar (50) about a horizontal axis. Preferably, the adapter (52) is also articulated with the rod (51) about a horizontal axis. The adapter (52) is also articulated with the cross member (5) along a vertical tracking axis (2), allowing the drawbar (50) and the beam (13) to form an angle, when viewed from above, with the main direction (D) when turning, avoiding or reducing the machine (1) from slipping on the surface (S).

[0024] It is clear from the above that the drawbar (50), the rod (51), the beam (13) and the adapter (52) form a four-bar mechanism. This four-bar mechanism is preferably a deformable parallelogram, which makes it possible to maintain the same position of the hitch frame (4) in the working and transport configurations, even when the machine (1) cannot pivot relative to the tractor (3) around a horizontal axis such as the hitch axis (16a, 16b).

[0025] As shown in [Fig.4], each tool (10) is associated with a lifting cylinder (21). The or each lifting cylinder (21) allows the tool (10) to be raised and lowered with which it is associated. More precisely, the or each lifting cylinder (21) allows the or each tool (10) to be moved away from its respective rollers (14). Each lifting cylinder (21) is hydraulic. Because the weight of the machine (1) can allow it to be lowered between its operating configuration and its working configuration, the or each lifting cylinder (21) is preferably single-acting. Sending pressurized oil to the or each lifting cylinder (21) then only allows the associated tool (10) to be raised. To move from the working configuration to the transport configuration, the lifting cylinder (21) of each tool (10) is extended. In the preferred embodiment, the or each lifting cylinder (21) is connected to the same distributor (32) as the return cylinders (11a, 11b).

[0026] When the tractor (3) and the machine (1) are moving on a flat surface, each return cylinder (11a, 11b) has a defined rest length. Preferably, the rest length of the two return cylinders (11a, 11b) is identical, so that when the tractor (3) and the machine (1) are moving on a flat surface, the coupling axes (16a, 16b) are the same. When the tractor (3) and / or the machine (1) is moving on a bumpy surface, the length of at least one return cylinder (11a, 11b) is modified because the return cylinders (11a, 11b) are mounted floating (connected to the hydraulic reservoir (33)) in the working configuration.

[0027] In the preferred embodiment, when the tractor (3) and the machine (1) are on a flat surface (S), the return cylinders (11a, 11b) are preferentially retracted, regardless of the configuration (work, transport or maneuver) of the machine (1). Indeed, the weight of the front tool (10), of the beam (13) and / or of the coupling frame (4) induces the retraction of the return cylinders (11a, 11b) on a flat surface. The resting length of a return cylinder (11a, 11b) is thus its minimum length.

[0028] When in the working configuration, a rear wheel of the tractor (3) is in a hole, the return cylinder (11a, 11b) located on the side of said rear wheel can extend. If, on the other hand, a rear wheel of the tractor (3) is on a mound, the return cylinder (11a, 11b) located on the opposite side of said rear wheel extends. It is clear from the above that allowing the free extension of the two return cylinders (11a, 11b) in the working configuration makes it possible to adapt to any type of unevenness of the surface (S), at least over a given range of movement. According to an interesting characteristic, each return cylinder (11a, 11b) is thus a single-acting cylinder, reducing the number of lines required and potentially hydraulic distributors to operate the machine (1), while allowing good adaptation of the machine (1) on a bumpy surface (S). In an alternative embodiment not shown, when the tractor (3) and the machine (1) are on a flat surface (S), the pistons of the return cylinders (11a, 11b) could however also be at mid-stroke or the return cylinders extended.

[0029] As shown in Figures 1, 3 and 4, the machine (1) is preferably a trailed windrower. In these figures, the or each tool (10) is a rotor provided with raking fingers (19). In the working configuration, the or each tool (10) can be rotated in a direction of rotation (R), so that the fingers (19) move product lying on the surface (S). The product is preferably plant-based, such as cut grass or cut straw. In the variants shown, each tool (10) is rotated about a respective substantially vertical drive axis (18), at least in the working configuration. A cam track guides the orientation of the fingers (19) according to their position around the drive axis (18), so that when the tool (10) is driven around its drive axis (18), the fingers (19) pivot along a horizontal axis.In order to rake the product located in front of each tool (10), the fingers (19) are substantially vertical when they are located in front of the drive axis (18). In order to move the product laterally, the tips of the fingers (19) are preferentially moved away from the surface (S) when the fingers (19) pivot along a horizontal axis. Alternatively, the machine (1) could be a trailed tedder or mower.

[0030] In the preferred variant of Figures 3 and 4, in order to reduce the width of the machine (1) in the transport configuration, the drive axis (18) of the rear tool (10) is substantially aligned with the drive axis (18) of the front tool (10) in the transport configuration and seen in the main direction (D). In the preferred variant of Figures 3 and 4, in the working and maneuvering configuration, the drive axis (18) of the rear tool (10) is offset relative to the drive axis (18) of the front tool (10), seen in the main direction (D). In this preferred variant, in the working configuration, the product raked by the front tool (10) is again raked by the rear tool (10), which forms a common windrow.In the preferred variant, the fingers (19) of the front and rear tools (10) are driven in the same direction of rotation and the fingers (19) located at the front of the tools (10) are driven towards the side of the rear tool (10), seen in the main direction, thus increasing the working width of the machine (1).

[0031] As can be seen from [Fig. 5], the machine (1) comprises at least one hydropneumatic accumulator (25). Specifically, the hydraulic circuit (40) of the machine (1) comprises at least one accumulator (25). As shown in [Fig.5], in the transport configuration, the hydraulic circuit (40) of the machine (1) is isolated from the hydraulic circuit (30) of the tractor (3).

[0032] As illustrated in [Fig.5], the accumulator (25) is configured to be hydraulically connected to the return cylinders (11a, 11b) in the transport configuration of the machine (1). Preferably, the hydraulic circuit (40) of the machine (1) is such that the accumulator (25) is hydraulically connected to the return cylinders (11a, 11b) in the transport and maneuvering configuration of the machine (1). Thus, each return cylinder (11a, 11b) exerts a force on the associated lever (6a, 6b), when the respective trunnion (7a, 7b) moves vertically relative to the crosshead (5). In the preferred embodiment, each return cylinder (11a, 11b) exerts a force on the associated lever (6a, 6b), when the respective trunnion (7a, 7b) moves downwards relative to the crosshead (5).Thus, the movements of the levers (6a, 6b) are blocked, respectively hindered, improving the handling of the machine (1) and advantageously preventing it from tipping over, in particular when turning. It is emphasized that in transport and maneuvering configurations, the center of gravity of the machine (1) is located higher than in the working configuration, because in the working configuration the or each tool (10) is closer to the surface (S), thus making the stability of the machine (1) particularly important in the transport and maneuvering configurations. Furthermore, the accumulator (25) is configured to keep the return cylinders (11a, 11b) at their rest length in the transport and maneuvering configurations. Preferably, the accumulator (25) is configured to exert a force keeping the return cylinders (11a, 11b) retracted in the transport configuration and in the maneuvering configuration.

[0033] It is clear from [Fig.4] that a central jack (24) connects the beam (13) on the one hand and one of the drawbar (50) and the rod (51) on the other hand. When the central jack (24) is actuated, it allows the beam (13) to be lifted substantially horizontally. Preferably, the central jack (24) connects the beam (13) and the drawbar (50). Even more preferably, a connecting rod is articulated with the drawbar (50) and the central jack (24).

[0034] As can be seen from [Fig. 2], in the preferred embodiment, each lever (6a, 6b) is pivotally mounted with the crosspiece (5) about a respective transverse axis (17a, 17b). Alternatively or additionally, each lever (6a, 6b) could slide relative to the crosspiece (5), in particular along an oblong hole having a vertical component. A sliding connection, however, often induces more wear than a pivot connection and generally complicates the kinematics. Thus, in a simple and economical manner, the connection between each lever (6a, 6b) and the crosspiece (5) is therefore achieved solely by a pivot. Preferably, the vertical displacement of each trunnion (7a, 7b) is made by pivoting around the respective transverse axis (17a, 17b), causing less premature wear. Thus, each return cylinder (11a, 11b) exerts a force on the associated lever (6a, 6b), when the respective trunnion (7a, 7b) pivots downwards relative to the crosspiece (5). In a balanced, simple and economical manner, the transverse axes (17a, 17b) are preferably merged.

[0035] As can be seen from [Fig. 6], at least one pad (22) may be provided between the cross member (5) and each lever (6a, 6b). Preferably, two pads (22) are fixed to each lever (6a, 6b) in order to absorb potential impacts between levers (6a, 6b) and cross member (5). The pads (22) are preferably made of flexible material such as rubber or elastomer. Such pads (22) make it possible to improve the comfort of the user or driver. Alternatively or additionally, a flexible pad (22) could be mounted at the inner end of the cylinder of each return cylinder (11a, 11b).

[0036] Preferably, the distributor (32) is connected at least to the central cylinder (24), to the lifting cylinders (21) and to the return cylinders (11a, 11b), thus reducing the number of hydraulic distributors necessary for actuating the machine (1). In addition, the central cylinder (24) and each of the lifting cylinders (21) are single-acting, reducing the cost of the machine (1) and its complexity. As previously described, in the working configuration of the machine (1), the distributor (32), in a floating position, makes it possible to connect the return cylinders (11a, 11b) to the reservoir (33). In the floating position, the distributor (32) therefore connects at least the central cylinder (24), the lifting cylinder(s) (21) and the return cylinders (11a, 11b) to the reservoir (33).

[0037] The distributor (32) can also occupy a passing configuration, in which it connects at least the return cylinders (11a, 11b) to the pump (31). In the passing configuration of the distributor (32), the central cylinder (24), the lifting cylinder(s) (21) and return cylinders (11a, 11b) are connected to the pump (31), thus moving the tool(s) (10) away from the surface. Respectively, to transpose the machine (1) from its working configuration into its maneuvering configuration, the distributor (32) is placed in the passing configuration. In the first variant, the maneuvering configuration corresponds to the transport configuration.

[0038] In the transport configuration, the distributor (32) prevents the retraction of the or each lifting cylinder (21), so that the or each tool (10) is kept further away from the surface (S) than in the working configuration. In the maneuvering configuration also, the distributor (32) prevents the retraction of the or each lifting cylinder (21). Preferably, the distributor (32) prevents any circulation of oil between the hydraulic circuit (30) of the tractor (3) and the hydraulic circuit (40) of the machine (1).

[0039] In the preferred variant of [Fig. 3], to transpose the machine (1) from its maneuvering configuration into its transport configuration, an additional jack (29) allows the rear tool (10) to be moved behind the front tool (10) in order to reduce the width of the machine (1). Respectively, the additional cylinder (29) allows the drive shaft (18) of the rear tool (10) to be moved behind the drive shaft (18) of the front tool (10). In this variant, the distributor (32) is connected to both the central cylinder (24), the lifting cylinders (21), the return cylinders (11a, 11b) and the additional cylinder (29).

[0040] Because the weight of the machine (1) allows the central cylinder (24), the lifting cylinders (21) and the return cylinders (11a, 11b) to retract to transpose the machine (1) from its transport or maneuvering configuration into its working configuration, the distributor (32) is placed in a floating configuration.

[0041] The machine (1) may comprise a distribution valve (27) which detects when the machine (1) is in the transport configuration. As shown in [Fig. 5], the distribution valve (27) detects when the central cylinder (24) is extended. When the distribution valve (27) detects that the machine (1) is in the transport configuration, the return cylinders (11a, 11b) are connected to the accumulator (25). More precisely, when the distribution valve (27) detects that the machine (1) is in the transport configuration, it connects the return cylinders (11a, 11b) to the accumulator (25). Thus, the distribution valve (27) may be a 2-2 distributor with a blocking position in at least one direction and a passing configuration. In the working configuration of the machine (1), the distribution valve (27) is in the blocking position.Thanks to this distribution valve, the user avoids an additional action and can advantageously not forget to connect the return cylinders (11a, 11b) to the tank (33) or to the accumulator (25).

[0042] In the working configuration, the accumulator (25) is not connected to the return cylinders (11a, 11b). On the other hand, at least when transposing the machine between its transport or maneuvering configuration and its working configuration, the accumulator (25) is hydraulically connected at least to the central cylinder (24), preferably in such a way that the central cylinder (24) exerts a force holding the beam (13) downwards, thus ensuring that the tool (10) (front) reaches its position in the working configuration, respectively that the tool (10) (front) is close to the surface (S), thus improving the working quality of the machine (1). Thanks to this hydraulic construction, the accumulator (25) makes it possible to fulfill a first function to reach the working configuration and a second function in the transport (and maneuvering) configuration, advantageously reducing the number of accumulators (25) required by the machine (1), and therefore its cost price.Preferably, in the working configuration, the central cylinder (24), the lifting cylinders (21), the return cylinders (11a, 11b) and the additional cylinder (29) are retracted.

[0043] The invention also relates to an agricultural convoy composed of a tractor (3) and of a machine (1).

[0044] The invention is not limited to the embodiment(s) and variants described and re-presented in the figures. Modifications remain possible from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. Agricultural machine (1) comprising at least one working tool (10) and a hitch frame (4) by which it is connected to a tractor (3), the hitch frame (4) comprising a cross member (5) and two levers (6a, 6b), each carrying a respective trunnion (7a, 7b) intended to be attached to a respective lower arm (8a, 8b) of the tractor (3) and capable of moving vertically relative to the cross member (5), each lever (6a, 6b) being associated with a return device (9a, 9b) capable of exerting a force on the associated lever (6a, 6b), when the respective trunnion (7a, 7b) moves vertically relative to the cross member (5), the machine (1) being able to occupy a working configuration in which the or each tool (10) is close to the surface (S) and at least one transport configuration, in which the or each tool (10) is further from the surface (S) than in the working configuration, machine (1) characterized in that each return device (9a,9b) comprises a hydraulic return cylinder (11a, 11b) fixed to the respective lever (6a, 6b) on one side and to the crosspiece (5) on the other side, each return cylinder (11a, 11b) being hydraulically connected to a hydraulic reservoir (33) in the working configuration.,

2. Machine according to claim 1, characterized in that each return cylinder (11a, 11b) is a single-acting cylinder and in that when the tractor (3) and the machine (1) are on a flat surface (S), the return cylinders (11a, 11b) are retracted.

3. Machine according to one of claims 1 or 2, characterized in that it comprises a hydropneumatic accumulator (25) configured to be hydraulically connected to the return cylinders (11a, 11b) in the transport configuration of the machine (1).

4. Machine according to any one of claims 1 to 3, characterized in that each lever (6a, 6b) is pivotally mounted with the crosspiece (5) around a respective transverse axis (17a, 17b).

5. Machine according to any one of claims 1 to 4, characterized in that two pads (22) are fixed to each lever (6a, 6b), in order to absorb potential shocks between the levers (6a, 6b) and the crosspiece (5).

6. Machine according to any one of claims 1 to 5, characterized in that it comprises a beam (13) connecting the at least one tool (10) to the coupling frame (4) by means of a drawbar (50), a central jack (24) connecting the beam (13) and the drawbar (50), in that each tool (10) is associated with a lifting cylinder (21) allowing the associated tool (10) to be raised and lowered, and in that a hydraulic distributor (32) is connected at least to the central cylinder (24), to the lifting cylinders (21) and to the return cylinders (11a, 11b).

7. Machine according to claim 6, characterized in that the central cylinder (24) and each of the lifting cylinders (21) are single-acting.

8. Machine according to claim 3 and any one of claims 4 to 7, characterized in that it comprises a distribution valve (27) detecting when the machine (1) is in transport configuration and connecting the accumulator (25) to the return cylinders (11a, 11b) when the machine (1) is in transport configuration.

9. Machine according to claim 3 and any one of claims 4 to 8, characterized in that, when transposing the machine (1) between its transport configuration and its working configuration, the accumulator (25) is hydraulically connected at least to the central cylinder (24), in such a way that the central cylinder (24) exerts a force holding the beam (13) downwards.

10. Machine according to any one of claims 1 to 9, characterized in that the or each tool (10) is a rotor provided with raking fingers (19) and capable of being driven in rotation in a direction of rotation (R), so that the fingers (19) move the product lying on the surface (S).

Images