Agricultural mower for push operation

Description

[0001] The present invention relates to an agricultural mower for operation in push mode according to the preamble of claim 1, a working train comprising a tractor and the mower, and a method for locking a mower unit of a mower in a central position.

[0002] To ensure good ground contour following in working position, implements such as mowers, which are mounted to the front of a tractor's linkage, are often suspended from a mounting frame with a pendulum-like mechanism, allowing them to pivot from side to side across the direction of travel. However, in the raised headland position and transport position, this type of suspension can cause the implement to swing uncontrollably. This can lead to it striking the ground or digging into the soil, especially when cornering. When transported on the road, the implement's pendulum swing can create dangerous situations for other road users, particularly when navigating roundabouts or during sudden evasive maneuvers. Furthermore, the back-and-forth swinging of the implement puts a sudden or jarring load on the tractor.

[0003] To counteract this, damping elements such as springs or elastomers are regularly incorporated to dampen the back-and-forth oscillation of the implement. However, this damping negatively impacts ground contour following in the working position, as this is also dampened by the damping elements. For example, when mowing, especially at high speeds, undamped oscillation is desirable for good results.

[0004] German patent application DE 10 2017 114 281 A1 discloses an attachment for a forage harvester, such as a corn header, with a lateral compensation cylinder that can be switched between two operating states. In the first operating state, the lateral compensation movement of the attachment is controlled, while in the second operating state the attachment can oscillate freely.

[0005] The object of the present invention is to create a mower suspended in such a way as to pendulum for mounting on a tractor, which avoids the above disadvantages and therefore does not tend to swing back and forth uncontrollably even in a raised position, particularly at the headland or during road transport, and on the other hand ensures good ground adaptation.

[0006] The problem is solved by a mower with the features of independent claim 1, a working train with the features of independent claim 11, and a method with the features of independent claim 14. Advantageous embodiments can be found in the dependent claims.

[0007] For this purpose, an agricultural mower is being developed. The mower is designed for push operation. It features a frame intended for mounting on a three-point linkage, such as that of a tractor. The three-point linkage can be located at the front of the tractor. However, it is also possible for the three-point linkage to be located at the rear of the tractor, allowing the tractor to be operated in reverse.

[0008] The mower features a cutting unit with a cutter bar that extends laterally, perpendicular to the mower's direction of travel. The cutting unit is pivotally mounted to the frame. This pivoting suspension allows the cutting unit to follow the ground around a pivot axis, moving from a central position in both directions relative to the frame. During operation, it glides over the field with a preferably adjustable ground pressure.

[0009] The pivot axis has a component extending in the direction of travel. It can also have a component extending vertically, perpendicular to both the direction of travel and the transverse direction. This ensures that the mower is oriented laterally even when pivoting in or against the direction of rotation.

[0010] The mower is characterized by the fact that it has a linear actuator with which the mower unit can be locked in the center position, especially in the raised position.

[0011] By locking, or fixing, the mower deck in the center position, it can no longer pivot in or against the direction of rotation. The linear actuator therefore prevents uncontrolled oscillation of the mower deck.

[0012] In principle, locking the mower unit is also possible in the field. However, the mower unit can then no longer be guided across the field in a ground-following manner. Therefore, the mower unit is preferably only locked in a raised position using the linear actuator, for example, during road transport and / or at a headland.

[0013] In the following, the operation of the mower with a lowered, ground-following mower unit is referred to as field operation.

[0014] The linear actuator is preferably arranged between the mower frame and the cutting unit. This allows the cutting unit to be locked in place by activating the linear actuator. The linear actuator can also be deactivated, so that the cutting unit can pivot relative to the frame when the linear actuator is deactivated. In a first preferred embodiment, the cutting unit can pivot freely relative to the frame when the linear actuator is deactivated, in particular without damping by a damping device. However, an embodiment in which the linear actuator is provided as a damping device to dampen the pivoting movement of the cutting unit relative to the frame is also preferred.

[0015] The linear actuator can be designed as an electric linear motor or as a pneumatically actuated linear actuator. However, it is preferred that it be designed as a hydraulic or electrohydraulic cylinder. A first linkage of the cylinder is then arranged on the frame of the mower, and a second linkage of the cylinder is then arranged on the mower unit, in particular on a strut of the mower unit.

[0016] In this embodiment, the cylinder can be activated by applying a locking pressure. The mower is therefore preferably configured to apply this locking pressure to the cylinder, thereby moving the mower unit into a neutral position. A single-acting connection on the cylinder is preferably used for this purpose. The locking pressure is then applied to this single-acting connection. It is preferred that the mower unit assumes a horizontal orientation in the neutral position on level ground. This ensures a consistent distance between the mower unit and the ground.

[0017] The cylinder can be deactivated by relieving the pressure, i.e., switching off the pressure, of the single-acting connection. During field operation, the cylinder can be completely relieved of pressure, i.e., without pressure. This allows the mower to pivot freely around its axis during field operation.

[0018] It is also preferred that the cylinder be designed as a damping element to dampen the pivoting movement about the pivot axis. In this embodiment, it is preferably designed as a double-acting cylinder. The cylinder then has a double-acting connection that is pressurized with a damping pressure to dampen the pivoting movement. This means that the cylinder is not (completely) pressureless during field operation, so that the mower can only pivot about the pivot axis with a damping force corresponding to the applied damping pressure.

[0019] The deactivated cylinder can therefore be pivoted continuously around its pivot axis, both in and against the direction of rotation, regardless of whether it is depressurized or pressurized. This allows for stepless adjustment to the terrain surface during field operation.

[0020] In a particularly preferred embodiment, the cylinder is designed as a double cylinder and therefore comprises two cylinder sections, each with a piston and a pressure chamber for receiving one of the two pistons. The pistons are reversibly displaceable linearly within their respective pressure chambers from an initial position to an end position. The double cylinder preferably has a single-acting connection for each piston to apply the locking pressure. Particularly preferably, the pressure chambers and / or pistons have the same dimensions, so that when the pistons are applied the same locking pressure, they move equally within their pressure chambers. This allows the neutral position to be set very easily by applying the same locking pressure to both pistons uniformly.

[0021] The single-acting ports of both pistons are preferably connected to each other by means of a connecting line. This connecting line allows for the simultaneous and uniform application of the locking pressure to both pistons in a very simple manner. It is preferred that both pistons are arranged in their end positions when the cylinder is in its central position.

[0022] Furthermore, preferably, in a retracted position of the cylinder, one of the two pistons is arranged in the starting position, and the other in the end position, and in an extended position of the cylinder, the first of the two pistons is arranged in the end position, and the other in the starting position.

[0023] The double-acting connection, which is particularly optional, for damping the pivoting motion around the pivot axis during field operation is preferably arranged on the piston section that is in its extended end position. To dampen the pivoting of the mower unit during field operation, it is further preferred that the two pressure chambers of the cylinder are connected to each other by a passage. This passage allows for pressure equalization between the two pressure chambers. This eliminates the need for a second double-acting connection on the second pressure chamber. The mower is preferably configured to apply damping pressure to the double-acting connection for damping the pivoting motion during field operation.

[0024] The task is further accomplished with a work unit comprising a tractor and an agricultural mower. The mower is mounted to the tractor's three-point linkage for push operation. The mower's cutting unit can be locked in the center position when raised, for example, at the headland and / or during road operation. This prevents the cutting unit from swinging back and forth, thus preventing it from hitting the ground, digging into the soil, and avoiding dangerous situations caused by the cutting unit pivoting around its axis during road travel. Furthermore, this prevents any sudden or jarring stress on the tractor.

[0025] Preferably, the mower can be reversibly raised from a working position in the field to a raised position at the headland and / or during road transport by lifting the lower links of the three-point linkage. The working linkage is preferably designed to lock the mower unit in the central position with the linear actuator when the mower is raised.

[0026] In a preferred embodiment, the linear actuator is designed as a hydraulic or electrohydraulic cylinder, in particular as a double cylinder with two cylinder parts. Each cylinder part has a piston that is movable back and forth in a pressure chamber.

[0027] The cylinder can be connected to a separate pressure supply, particularly that of the tractor. However, to lock the mower in the center position, it is preferred that a connecting line for applying (lifting) pressure to the lower links of the three-point linkage is linked to a connecting line for applying the locking pressure to the pistons. This automatically moves the cylinder to the center position when the lower links of the tractor's three-point linkage are raised, thus locking the mower.

[0028] The problem is further solved by a method for locking the mower unit of an agricultural mower, in particular an agricultural mower according to the invention, in which a hydraulic cylinder is pressurized with a locking pressure, so that the cylinder moves into a central position and locks the mower unit in a central position. The cylinder can be designed as a double cylinder with two pistons, both of which are moved into an end position when the cylinder is pressurized with the locking pressure. The method can be executed automatically when the mower is lifted and is therefore very convenient and easy to use for the operator.

[0029] The invention is described below with reference to figures. The figures are merely exemplary and do not limit the general concept of the invention. They show Fig. 1 in (a) schematically shows a work train with a tractor and a mower, and in (b) the mower in a side view with a partial section through a frame of the mower; Fig. 2 in (a) - (c) the work train in a front view, wherein the mower is shown in (a) and (c) in different pivot positions, and in (b) in a central position; and Fig. 3 in (a) - (c) a cylinder for locking a mower unit of the mower in different positions.

[0030] Fig. 1 Figure (a) shows a work train with a tractor 1, of which only a front part is shown schematically here, and a mower 2. For clarification, the front wheels 11 of the tractor 1 are shown.

[0031] The mower 2 is attached in the conventional manner to a three-point linkage 12 of the tractor 1, which is located at the front of the tractor 1, so that the tractor 1 carries the mower 2. For this purpose, the mower 2 has a frame 21. The frame has two V-shaped arms 22, each of which is attached at its end to a lower link 13 of the three-point linkage. The connection of the frame 21 to one of the lower links 13 of the three-point linkage 12 is shown here. The frame 21 can be attached to a top link (not shown) of the three-point linkage 12 via a connection point (not labeled) of the arms 22. This connection point is not shown here for clarity.

[0032] Furthermore, a power take-off (PTO) connection 14 of the tractor 1 is visible. The drive of the mower 2, in particular a PTO shaft, is also carried out in a conventional manner and is not shown for the sake of clarity.

[0033] The mower 2 is positioned at the front of the tractor 1 and is operated in push mode. The working unit moves in one direction 51.

[0034] The mower 2 has a mower unit 26, which extends in a transverse direction 53 perpendicular to the direction of travel 51 of the working unit. A cutter bar 25 is arranged on the mower unit 26, which rests on the field ground (not shown) during field operation. The contact pressure of the cutter bar 25 on the field ground can be adjusted by means of force (not shown) arranged between the three-point linkage 12 and the frame 21.

[0035] To ensure that the mower 26 can continue to be guided over the field, particularly in heavily undulating terrain, with consistent ground pressure, it is pivotally suspended from the frame 21 of the mower 2. For this purpose, two spaced-apart ball joint bearings S, 27 are provided on the frame 21 of the mower 26, on which the mower 26 is suspended, such that a connecting line between the two bearings S, 27 forms a pivot axis 20 about which the mower 26 pivots in and against a pivot direction 50 (see figure). Fig. 2 ) is pivotable back and forth. One of the two ball joint bearings S is located here at the center of gravity of the mower unit 26. However, another pivot point (not shown) for suspending the mower unit 26 is also conceivable. Due to the components of the mower unit 26, the center of gravity may be located off-center, especially with a single-sided drive. The pivot axis 20 has extension components only in the direction of travel 51 and in the vertical direction 52, so that the mower unit 26 is also aligned in the transverse direction 53 when pivoting back and forth about the pivot axis 20.

[0036] To lock the mower unit 26 in a central position M, the mower 2 has a linear actuator 3, which is designed here as a hydraulic cylinder. Therefore, the terms linear actuator 3 and cylinder will be used synonymously in the following.

[0037] The cylinder 3 is articulated between a linkage 23 on the frame 21 of the mower 2 and a linkage 24 on the mower unit 26, for example on a strut (not shown) of the mower unit 26.

[0038] Fig. 1 (b) shows the mower 2 in a side view, with the Fig. 1 (b) Figure 2 shows the mower 2 with a partial section through the frame 21, so that the ball joint bearings S, 27 and the cylinder 3 with its linkages 23, 24 are visible. In the Fig. 1 (a) und (b) The mower 2 is positioned in the central position M. The cylinder 3 is in a central position T (see figure). Fig. 3 (b) ).

[0039] The Fig. 2 Figures (a) - (c) show the working unit in a front view, with the mower 2 shown in (a) and (c) in different pivot positions W, in which the mower unit 26 is pivoted about the pivot axis 20 relative to the center position M, and in (b) in the center position M. The pivot positions W and the center position M are indicated relative to a horizontal reference line 4.

[0040] In a first pivot position W, which Fig. 2 (a) As shown, the mower unit 26 is pivoted in the pivot direction 50 about the pivot axis 20. As a result, the cylinder 3 is in a retracted position E (see figure). Fig. 3 (a) ). In Fig. 2 (b) The mower unit 26 is arranged in the central position M. It is then neither pivoted in nor against the pivot direction 50 about the pivot axis 20. On level ground, the mower unit 26 is then horizontally aligned. As a result, the cylinder 3 is in a central position T (see figure). Fig. 3 (a) ). In a second pivot position W, which is in Fig. 2 (c) As shown, the mower unit 26 is pivoted against the direction of rotation 50. This places the cylinder 3 in an extended position A (see figure). Fig. 3 (c) ).

[0041] Fig. 3 shows cylinder 3 in (a) in the retracted position, in (b) in the middle position, and in (c) in the extended position A.

[0042] The cylinder 3 is designed here as a double cylinder. Therefore, in this figure, the terms cylinder 3 and double cylinder are used synonymously. The cylinder 3 has two cylinder parts 31, 35, each with a piston 32, 36 and a pressure chamber 33, 37, wherein the piston 32, 36 is displaceable back and forth within the pressure chamber 33, 37 in which it is located.

[0043] With pressureless pressure chambers 33, 37, each piston 32, 36 is freely movable back and forth within its respective pressure chamber 33, 37. This allows both pistons 32, 36 to be moved from an initial position a to an end position e and back again. During this movement, the cylinder 3 is continuously adjusted from the retracted position E, in which the first of the two pistons 32 is in the end position e and the other piston 36 is in the initial position a, to the extended position A, in which the first piston 32 is in the initial position a and the other piston 36 is in the end position e. The intermediate position T, in which both pistons 32, 36 are in the end position e, is passed through during this movement.

[0044] To pressurize the pressure chambers 33, 37, both cylinder parts 31, 35 each have a single-acting port 34, 38. The single-acting ports 34, 38 are each located on the outlet side of the pressure chambers 33, 37. By pressurizing the single-acting ports 34, 38 with the pressure, in particular the locking pressure, the pistons 32, 36 can therefore each be displaced from the initial position a to the end position e.

[0045] Furthermore, one of the cylinder parts 35 has a double-acting port 39, which is arranged at the end of its pressure chamber 37. By applying pressure, in particular the damping pressure, to the double-acting port 39, the piston 36 of this cylinder part 35 can be moved from the end position e to the initial position a. In order to apply the damping pressure equally to both cylinder parts 31, 35, the two pressure chambers 33, 37 of the cylinder parts 31, 35 are connected by a passage 30 (see figure). Fig. 3 (c) ), which is arranged in particular in an intermediate wall (not designated) between the pressure chambers 33, 37, are connected to each other. This allows pressure equalization between the two pressure chambers 33, 37 of the cylinder 3, so that the other piston 32 is also moved.

[0046] The dimensions of the cylinder parts 31, 35, in particular the pressure chambers 33, 37 and pistons 32, 36, are all the same. When subjected to the same pressure, the pistons 32, 36 are therefore displaced equally within their pressure chambers 33, 37.

[0047] When cylinder 3 is deactivated, it is either depressurized, so that no pressure is applied to either the single-acting ports 34, 38 or the double-acting port 39. Alternatively, a damping pressure may be applied to the double-acting port 39, which dampens the movement of the cylinder parts 31, 35.

[0048] With cylinder 3 activated, the single-acting ports 34 and 38 are subjected to a holding pressure B. This pushes both pistons 32 and 36 into their end position e. No pressure then acts on the double-acting port 39. Cylinder 3 is then in the neutral position T. Fig. 2 (b) shows.

[0049] To prevent dangerous situations in road traffic, as well as the mower 26 digging into the ground or striking the ground, the single-acting connections 34, 38 are connected here via a Fig. 3 (a)The connecting lines 348, shown only schematically as an example, are connected to each other and to the hydraulic lines (not shown) of the lower links 13 of the three-point linkage 12. This means that the mower 26 is automatically locked in the center position M when the mower 2 is raised, for example during road transport and / or at the headland. Operation is therefore very simple and convenient for the driver.

Claims

1. Agricultural mower (2) which is designed for operation in overrun mode and comprises a frame (21) for mounting on a three-point hitch (12) of a tractor (1), wherein the mower (2) has a mowing unit (26) having a cutter bar (25) which extends transversely to a direction of travel (51), wherein the mowing unit (26) is pivotally suspended on the frame (21) so that, in field operation, it can pivot back and forth about a pivot axis (20), starting from a central position (M), in and counter to a pivot direction (50) relative to the frame (21) so as to adapt to the ground surface, wherein the mower (2) has a linear actuator by means of which the mowing unit (26) can be locked in the central position (M) in a raised placement, which is assumed in the headland and / or during road operation, wherein the mowing unit (26) is automatically locked in the central position (M) when the mower (2) is raised.

2. Agricultural mower (2) according to claim 1, characterized in that the linear actuator is arranged between the frame (21) of the mower (2) and the mowing unit (26).

3. Agricultural mower (2) according to either of the preceding claims, characterized in that the linear actuator is a hydraulic or electrohydraulic cylinder (3).

4. Agricultural mower (2) according to claim 3, characterized in that it is designed to apply a locking pressure to the cylinder (3) in order to lock the mowing unit (26) in the central position (M) so that the cylinder is adjusted into a central placement (T).

5. Agricultural mower (2) according to either of claims 3 to 4, characterized in that the cylinder (3) is either unpressurized in field operation or is provided as a damping means for damping the pivoting movement about the pivot axis (20).

6. Agricultural mower (2) according to any of claims 3 to 5, characterized in that the cylinder (3) has two cylinder parts (31, 35), each having a piston (32, 36) and a pressure chamber (33, 37) for receiving the piston (32, 36), the pistons (32, 36) each being linearly movable in their pressure chamber (33, 37) from an initial position (a) to an end position (e).

7. Agricultural mower (2) according to claim 6, characterized in that the cylinder (3) has a single-acting connection point (34, 38) for each of the pistons (32, 36) in order to apply the locking pressure to the pistons (32, 36), the connection points being connected to one other by means of a connecting line (348).

8. Agricultural mower (2) according to either of claims 6 to 7, characterized in that in the central placement (T) of the cylinder (3), the two pistons (32, 36) are arranged in the end position (e).

9. Agricultural mower (2) according to any of claims 6 to 8, characterized in that in a retracted placement (E) of the cylinder (3), a first of the two pistons (32, 36) is arranged in the starting position (a), and the other is arranged in the end position (e), and in that in an extended position (A) of the cylinder (3), the first of the two pistons (32, 36) is arranged in the end position (e), and the other is arranged in the starting position (a).

10. Agricultural mower (2) according to any of claims 6 to 9, characterized in that the two pressure chambers (33, 37) are connected to one other by means of a passage (30), the cylinder (3) having a double-acting connection point (39) for applying a damping pressure to one of the two pressure chambers (33, 37), the mower (2) being designed to apply the damping pressure to the double-acting connection point (39) in field operation in order to damp the pivoting movement.

11. Work train comprising a tractor (1) and an agricultural mower (2) according to any of the preceding claims, which mower is attached to a three-point hitch (12) of the tractor (1) for operation in overrun mode.

12. Work train according to claim 11, characterized in that the mower (2) can be reversibly raised from a working placement in field operation into a raised placement in the headland and / or during road transport by raising lower links (13) of the three-point hitch (12), the work train being designed to lock the mowing unit (26) in the central position (M) using the linear actuator when the mower (2) is raised.

13. Work train according to claim 12, characterized in that the linear actuator is designed as a cylinder (3) having two cylinder parts (31, 35), each comprising a piston (32, 36) which is can be moved back and forth in a pressure chamber (33, 37), a connection line for applying a lifting pressure to the lower links (13) of the three-point hitch (12) being connected to a connecting line (348) for applying a locking pressure to the pistons (32, 36) in order to lock the mowing unit (26) in the central position (M).

14. Method for locking a mowing unit (26) of an agricultural mower (2) according to any of claims 1-10, in which method a locking pressure is applied to a hydraulic cylinder (3), in particular a double cylinder having two pistons (32, 36), so that the cylinder (3) is adjusted into a central placement (T) and locks the mowing unit (26) in a central position (M).