Agricultural machine 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 includes a crossbar 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 crossbar, 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 crossbar, the machine being able to occupy a working configuration in which the tool or tools are close to the surface and at least one transport configuration, in which the tool or tools are further from the surface than in the working configuration, each return device comprising a hydraulic return cylinder fixed to the respective lever on one side and to the crossbar on the other side.Each return cylinder is hydraulically connected to a hydraulic reservoir in the working configuration. Figure to be published with the abbreviation: 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 crossbar and two levers, each lever carrying a respective trunnion intended to be attached to a respective lower arm of the tractor and being able to move vertically relative to the crossbar, each lever being associated with a return device able to exert a force on the associated lever, when the respective trunnion moves vertically relative to the crossbar, the machine being able to occupy a working configuration in which the tool or each tool is close to the surface, and at least one transport configuration in which the tool 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 A1L. In this document, the return device comprises elastically deformable elements that store and release energy to the associated trunnion when it moves vertically. Such return devices reduce the risk of the machine tipping over in transport configuration by storing force and releasing it to the lever(s) to return them to their initial position. In the machine's working configuration, the elastically deformable elements of these return devices also transmit forces between the tractor and the machine when a trunnion is moved vertically relative to the machine's hitch frame, which could result in a shorter service life for both the tractor's hitch and the machine's hitch frame.Furthermore, the elastically deformable elements also imply a limited range of trunnion movement, resulting in limited machine adaptation to a bumpy surface, which can lead to lower work quality, as well as damage to the tools and / or the surface.

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

[0004] For this purpose, each return device includes 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 working configuration.

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

[0006] The invention will be better understood from the following description, which relates to various preferred embodiments, given by way of non-limiting examples, and explained with reference to the accompanying 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 concealed,

[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 embodiment 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 schematic representation of the machine's hydraulic circuit according to the preferred variant, the machine's hydraulic circuit being connected to the tractor's hydraulic circuit, and,

[0012] [Fig.6] represents a side section view of the coupling of [Fig.2], the location of the section being shown on [Fig.1].

[0013] As shown in [Fig. 1], the agricultural machine (1) according to the invention comprises at least one implement (10). The machine (1) also comprises a hitch 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 hitch device comprising a left lower arm (8a) and a right lower arm (8b). The tractor (3) is capable of moving with or without the machine (1) in a principal 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 working. The tractor (3) also enables the machine (1) to be driven, in particular by means of 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, back, in front, behind, right and left are defined looking in the principal direction (D).

[0015] The machine (1) also includes at least one beam (13). The beam (13) connects at least one implement (10) to the hitch frame (4). Preferably, the beam (13) connects at least one implement (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 hitched to the rear hitch of the tractor (3). In a embodiment not shown, the machine (1) could however be attached to the front hitch device of the tractor (3).

[0016] The machine (1) includes a hydraulic circuit (40). The tractor (3) also includes a hydraulic circuit (30). The hydraulic circuit (30) of the tractor (3) includes at least one reservoir (33). The hydraulic circuit (30) of the tractor (3) also includes 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) allows pressurized oil to be sent 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) has 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 refer to these symmetrical parts to the left of the central plane (P) as a and those to the right as b. Thus, it is agreed to refer to a first lever as the left lever (6a), and a second lever as the right lever (6b). Similarly, it is also agreed to name a first trunnion as the left trunnion (7a) and a second trunnion as the right trunnion (7b), etc. Thus, the first trunnion (7a) is attached to the lower left arm (8a) of the tractor hitch device (3) and the second trunnion (7b) is attached to the lower right arm (8b) of the tractor hitch device (3).The vertical is orthogonal to the principal direction (D) and to the line passing through the trunnions (7a, 7b).

[0018] To allow for proper adaptation of the machine (1) relative to the tractor (3) when moving over a bumpy surface (S), each trunnion (7a, 7b) can move vertically relative to the cross member (5). Furthermore, each trunnion (7a, 7b) is articulated with the associated lever (6a, 6b) around a hitch pin (16a, 16b). Each hitch pin (16a, 16b) is horizontal. Each hitch pin (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 trunnion (7a, 7b) moves vertically relative to the cross member (5).

[0020] In the first embodiment of [Fig. 1], 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 hinge. allowing at least one pivoting about a substantially vertical central axis (12). As shown in [Fig. 3], the machine (1) can be in a working configuration in which the tool(s) (10) is close to the surface (S). As shown in [Fig. 4], the machine (1) can also be in a transport configuration in which the tool(s) (10) is further from the surface (S) than in the working configuration.

[0021] The machine (1) can preferably also be in a maneuvering configuration, in which the tool(s) (10) are also further from the surface (S). In the first variant of [Fig. 1], 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 configurations. The machine (1) rests on the surface (S) by means of rollers (14), 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 feature of the invention, each return device (9a, 9b) comprises a hydraulic return cylinder (lia, 11b). Each return cylinder (lia, 11b) is attached to the respective lever (6a, 6b) on one side and to the cross member (5) on the other. Each return cylinder (lia, 11b) is connected to the respective lever (6a, 6b) by its rod or cylinder. Each return cylinder (lia, 11b) is also connected to the cross member (5) by that part of its rod or cylinder which is not connected to the respective lever (6a, 6b). In the working configuration, each return cylinder (lia, 11b) is hydraulically connected to a hydraulic reservoir (33). The return cylinders (lia, 11b) are said to be floating mounted. In this way, the extension of each return cylinder (lia, 11b) is free in working configuration.Thus, the machine's (1) movements are freer in working configuration, improving its ability to adapt to a bumpy surface (S) and reducing stress on the hitch frame (4) and the tractor's hitching device (3) when moving the machine (1) over a bumpy surface (S).

[0023] As shown in [Fig. 4], the tiller (50) and a rod (51) are each articulated with the beam (13) about a respective horizontal axis. An adapter (52) is articulated with at least the tiller (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) about a vertical tracking axis (2), allowing the tiller (50) and the beam (13) to form an angle, in top view, with the main direction (D) when turning, avoiding or reducing slippage of the machine (1) on the surface (S).

[0024] It follows 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 lifting cylinder (21) raises and lowers the tool (10) to which it is attached. More precisely, the lifting cylinder (21) moves the tool (10) away from its respective rollers (14). Each lifting cylinder (21) is hydraulic. Because the weight of the machine (1) can lower it between its maneuvering and working configurations, the lifting cylinder (21) is preferably single-acting. Sending pressurized oil to the lifting cylinder (21) then only raises the associated tool (10). To switch from the working configuration to the transport configuration, the lifting cylinder (21) of each tool (10) is extended. In the preferred embodiment, the lifting cylinder or each lifting cylinder (21) is connected to the same distributor (32) as the return cylinders (lia, 11b).

[0026] When the tractor (3) and the machine (1) move on a flat surface, each return cylinder (lia, 11b) has a defined rest length. Preferably, the rest length of both return cylinders (lia, 11b) is identical, so that when the tractor (3) and the machine (1) move on a flat surface, the hitch pins (16a, 16b) coincide. When the tractor (3) and / or the machine (1) move(s) on a bumpy surface, the length of at least one return cylinder (lia, 11b) is modified because the return cylinders (lia, 11b) are mounted in a floating position (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 (lia, 11b) are preferentially retracted, regardless of the configuration (working, transporting, or maneuvering) of the machine (1). This is because the weight of the front implement (10), the beam (13), and / or the hitch frame (4) causes the return cylinders (lia, 11b) to retract on a flat surface. The resting length of a return cylinder (lia, 11b) is thus its minimum length.

[0028] When in working configuration, if a rear wheel of the tractor (3) is in a hole, the return cylinder (lia, 11b) located on the side of said rear wheel can extend. Conversely, if a rear wheel of the tractor (3) is on a mound, the return cylinder (lia, 11b) located on the opposite side of said rear wheel extends. It follows from the above that allowing the free extension of both return cylinders (lia, 11b) in working configuration makes it possible to adapt to any type of unevenness in the surface (S). at least over a given range of motion. According to an interesting feature, each return cylinder (1a, 11b) is thus a single-acting cylinder, reducing the number of lines and potentially hydraulic valves required to operate the machine (1), while still allowing the machine (1) to adapt well to an uneven 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 (1a, 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 rake. In these figures, the tool or tools (10) is a rotor equipped with raking tines (19). In the working configuration, the tool or tools (10) can be driven in rotation in a direction of rotation (R), so that the tines (19) move material lying on the surface (S). The material is preferably plant matter, such as cut grass or cut straw. In the variants shown, each tool (10) is driven in rotation about a respective substantially vertical drive axis (18), at least in the working configuration. A cam track helps to guide 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.To rake the product located in front of each tool (10), the fingers (19) are substantially vertical when positioned in front of the drive shaft (18). To move the product laterally, the tips of the fingers (19) are preferentially away from the surface (S) when the fingers (19) pivot about a horizontal axis. Alternatively, the machine (1) could be a trailed tedder or mower.

[0030] In the preferred embodiment shown in Figures 3 and 4, in order to reduce the width of the machine (1) in the transport configuration, the drive shaft (18) of the rear tool (10) is substantially aligned with the drive shaft (18) of the front tool (10) in the transport configuration and viewed along the main direction (D). In the preferred embodiment shown in Figures 3 and 4, in the working and maneuvering configuration, the drive shaft (18) of the rear tool (10) is offset relative to the drive shaft (18) of the front tool (10), viewed along the main direction (D). In this preferred embodiment, in the working configuration, the product raked by the front tool (10) is raked again by the rear tool (10), which forms a common swath.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 in the direction of the side of the rear tool (10), seen along the main direction, thus increasing the working width of the machine (1).

[0031] As shown in [Fig. 5], the machine (1) includes at least one hydropneumatic accumulator (25). Specifically, the hydraulic circuit (40) of the machine (1) includes at least one accumulator (25). As shown in [Fig. 5], in 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 (lia, 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 (lia, 11b) in the transport and maneuvering configuration of the machine (1). Thus, each return cylinder (lia, 11b) exerts a force on the associated lever (6a, 6b) when the respective trunnion (7a, 7b) moves vertically relative to the cross member (5). In the preferred embodiment, each return cylinder (lia, 11b) exerts a force on the associated lever (6a, 6b) when the respective trunnion (7a, 7b) moves downward relative to the cross member (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, particularly when turning. It is noted 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 tool(s) (10) are closer to the surface (S), thus making the stability of the machine (1) particularly important in transport and maneuvering configurations. Furthermore, the accumulator (25) is configured to maintain the return cylinders (lia, 11b) at their rest length in transport and maneuvering configurations. Preferably, the accumulator (25) is configured to exert a force keeping the return cylinders (lia, 11b) retracted in both the transport and maneuvering configurations.

[0033] It can be seen from [Fig. 4] that a central jack (24) connects the beam (13) on one side to one of the drawbar (50) and the rod (51) on the other. When the central jack (24) is actuated, it allows the beam (13) to be raised 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 in [Fig. 2], in the preferred embodiment, each lever (6a, 6b) is pivotally mounted with the cross member (5) about a respective transverse axis (17a, 17b). Alternatively or additionally, each lever (6a, 6b) could slide relative to the cross member (5), in particular along an oblong hole having a vertical component. However, a sliding joint often induces more wear than a pivot joint and generally complicates the kinematics. Thus, of In a simple and economical manner, the connection between each lever (6a, 6b) and the cross member (5) is therefore achieved solely by a pivot. Preferably, the vertical movement of each trunnion (7a, 7b) is achieved by pivoting around its respective transverse axis (17a, 17b), resulting in less premature wear. Thus, each return cylinder (11a, 11b) exerts a force on its associated lever (6a, 6b) when its respective trunnion (7a, 7b) pivots downwards relative to the cross member (5). For a balanced, simple, and economical solution, the transverse axes (17a, 17b) are preferably aligned.

[0035] As shown in [Fig. 6], at least one pad (22) can be provided between the cross member (5) and each lever (6a, 6b). Preferably, two pads (22) are attached to each lever (6a, 6b) to absorb potential shocks between the levers (6a, 6b) and the cross member (5). The pads (22) are preferably made of a flexible material such as rubber or elastomer. Such pads (22) 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 (1a, 1b).

[0036] Preferably, the distributor (32) is connected at least to the central cylinder (24), the lifting cylinders (21), and the return cylinders (lia, 11b), thus reducing the number of hydraulic distributors required to actuate the machine (1). Furthermore, the central cylinder (24) and each of the lifting cylinders (21) are single-acting, reducing the cost and complexity of the machine (1). As described previously, in the working configuration of the machine (1), the distributor (32), in a floating position, connects the return cylinders (lia, 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 (lia, 11b) to the reservoir (33).

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

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

[0039] In the preferred embodiment of [Fig. 3], to move the machine (1) from its maneuvering configuration to its transport configuration, an additional cylinder (29) allows the rear tool (10) to be moved behind the front tool (10), in order to reduce the width of the machine (1). Conversely, 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 embodiment, the distributor (32) is connected to 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 (lia, 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 include a distribution valve (27) that 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 (1a, 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 (1a, 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 cannot advantageously forget to connect the return cylinders (lia, 11b) to the reservoir (33) or the accumulator (25).

[0042] In the working configuration, the accumulator (25) is not connected to the return cylinders (1a, 11b). However, at least during the transposition of 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, or that the tool (10) (front) is close to the surface (S), thereby improving the working quality of the machine (1). Thanks to this hydraulic construction, the accumulator (25) fulfills 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 for the machine (1), and therefore its cost.Preferably, in the configuration of . work, the central cylinder (24), the lifting cylinders (21), the return cylinders (lia, 11b) and the additional cylinder (29) are retracted.

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

[0044] The invention is not limited to the embodiment(s) and variants described and shown in the figures. Modifications remain possible with regard to the construction of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Demands

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 tool or tools (10) are close to the surface (S) and in which each tool (10) is driven in rotation about an axis training (18) respective substantially vertical, and at least one transport configuration,in which the tool 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 (lia, 11b) fixed to the respective lever (6a, 6b) on one side and to the cross member (5) on the other side, each return cylinder (lia, 11b) being hydraulically connected to a hydraulic reservoir (33) in the working configuration such that the extension of each return cylinder (lia, 11b) is free in the working configuration.

2. Machine according to claim 1, characterized in that each return cylinder (lia, 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 (lia, 11b) are retracted.

3. Machine according to any one of claims 1 or 2, characterized in that it comprises a hydropneumatic accumulator (25) configured to be hydraulically connected to the return cylinders (lia, 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 cross member (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 cushion potential shocks between the levers (6a, 6b) and the crossbar (5).

6. Machine according to any one of claims 1 to 5, characterized in that it comprises a beam (13) connecting at least one tool (10) to the hitch frame (4) by means of a drawbar (50), a central cylinder (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), the lifting cylinders (21) and the return cylinders (1a, 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 (lia, 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, during the transposition of 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 tool or each tool (10) is a rotor having raking fingers (19) and can be driven in rotation in a direction of rotation (R), so that the fingers (19) move the product lying on the surface (S).

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