Switchable Cutter Bar Drive for Agricultural Attachment

Abstract

An agricultural attachment is provided with a cutter bar and a hydraulic motor for oscillatingly driving the cutter bar via an eccentric gear. The hydraulic motor is connected via a feed line and a return line to a hydraulic loaded with a hydrostatic liquid by a hydraulic pump. A switchover valve is integrated in the hydraulic circuit and switches pressure-dependently, wherein the switchover valve has a first switch position and a second switch position and is adjustable back and forth between the first switch position and the second switch position. The hydraulic motor is driven in the first switch position in a first rotational direction and is driven in the second switch position in a second rotational direction, wherein the second rotational direction is opposite to the first rotational direction.

Claims

1. An agricultural attachment comprising: a cutter bar; a hydraulic motor configured to oscillatingly drive the cutter bar via an eccentric gear; a hydraulic circuit loaded with a hydrostatic liquid by a hydraulic pump, wherein the hydraulic motor is configured to connect via a feed line and a return line to the hydraulic circuit; a switchovervalve integrated in the hydraulic circuit and configured to switch pressure-dependently, wherein the switchover valve comprises a first switch position and a second switch position and is configured to be adjusted back and forth between the first switch position and the second switch position; wherein the hydraulic motor is driven in the first switch position in a first rotational direction and is driven in the second switch position in a second rotational direction, wherein the second rotational direction is opposite to the first rotational direction.

2. The agricultural attachment according to claim 1, further comprising a pressure limiting valve arranged in the feed line of the hydraulic circuit upstream of the switchover valve in a flow direction of the hydraulic liquid, wherein the pressure limiting valve comprises a relief opening, wherein the relief opening is pressure-connected to an actuation device configured to switch the switchover valve.

3. The agricultural attachment according to claim 2, wherein the hydraulic motor, the switchover valve, the pressure limiting valve, and a first part of the hydraulic circuit are arranged at the agricultural attachment, wherein the agricultural attachment further comprises an interface, wherein the interface is configured to connect the first part of the hydraulic circuit to a second part of the hydraulic circuit located in a combine harvester to which the agricultural attachment is attachable.

4. The agricultural attachment according to claim 1, further comprising a pressure sensor arranged in the feed line of the hydraulic circuit upstream of the switchover valve in a flow direction of the hydraulic liquid, wherein the pressure sensor is connected to an actuation device configured to switch the switchover valve and configured to transmit a control signal to the actuation device when a preselected threshold value is surpassed.

5. The agricultural attachment according to claim 4, wherein the hydraulic motor, the switchover valve, the pressure sensor, and a first part of the hydraulic circuit are arranged at the agricultural attachment, wherein the agricultural attachment further comprises an interface, wherein the interface is configured to connect the first part of the hydraulic circuit to a second part of the hydraulic circuit located in a combine harvester to which the agricultural attachment is attachable.

6. The agricultural attachment according to claim 1, wherein the hydraulic motor is configured to be switched on and off by a hydraulic multi-way valve.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0016] FIG. 1 shows an agricultural attachment 2 that can be attached to a combine harvester and is provided with a cutter bar 20.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0017] In FIG. 1, an agricultural attachment 2 is illustrated that can be attached to a combine harvester, not illustrated here. The agricultural attachment 2 can be, for example, a grain header or a mower. A cutter bar 20 is arranged at the attachment 2 and, during harvesting, is moved into the standing crop and in doing so cuts the stalks of the crop. The cut crop is then pulled in by the attachment 2 and conveyed to the associated combine harvester.

[0018] The attachment 2 is provided with a hydraulic circuit 6 through which a hydraulic liquid is circulating which is supplied by the hydraulic pump 4. The hydraulic liquid is sucked in by the hydraulic pump 4 from the tank 8 and pumped into the feed line 10. Through the return line 12, the hydraulic liquid is returned again to the tank 8 after it has passed through the hydraulic motor 18.

[0019] Between the hydraulic pump 4 and the tank 8, on the one hand, and the hydraulic motor 18, on the other hand, a switchover valve 14 is provided in the hydraulic circuit 8. The hydraulic motor 18 is designed to operate in two rotational directions 30. Depending on the rotational direction, the hydraulic motor 18 moves the cutter bar 20 via an eccentric gear 22 to the right or to the left. In the embodiment, the eccentric gear 22 is comprised of a hydraulic motor-side drive disk, a coupling rod 24 which is eccentrically connected to the drive disk, and a bearing pin that is connected rigidly to the movable part of the cutter bar 20. By means of the eccentric gear, the rotational movement of the drive disk is converted into an oscillating movement of the movable part of the cutter bar 20.

[0020] The direction in which the hydraulic motor 18 rotates depends on in which switch position the switchover valve 14 is arranged. In FIG. 1, a 4/2 way valve is illustrated with which the hydraulic motor 18 is driven in opposite direction in the two illustrated switch positions A, B, respectively. When the switch position of the switchover valve 14 is changed from the switch position A into the switch position B or vice versa, the movement direction of the movable part of the cutter bar 20 is immediately changed mandatorily in this way.

[0021] In the embodiment illustrated in FIG. 1, a pressure limiting valve 16 is located in the feed line 10 between the hydraulic pump 4 and the switchover valve 14. When in the feed line 10 a pressure exists that surpasses a preadjusted threshold value, a relief opening 26 opens through which the hydraulic liquid can escape from the pressure limiting valve 16. The hydraulic liquid which is escaping from the pressure limiting valve 16 acts on the pressure actuation 28 with which the switchover valve 14 can be switched back and forth between one of the switch positions A, B. Thus, when in the feed line 10 an excess pressure occurs, the rotational direction of the hydraulic motor 18 changes automatically.

[0022] In FIG. 1, the interface 32 between an attachment 2 and a combine harvester to which the attachment 2 can be attached is indicated by a dashed line. In the proposed distribution, the hydraulic pump 4 and the tank 8 are located on the combine harvester while the other components of the hydraulic circuit 6 are arranged at the attachment 2.

[0023] Instead of the switching action of the switchover valve 14 by the pressure limiting valve 16, it is also possible to effect the switching action of the switchover valve 14 by a pressure sensor 34. The pressure sensor 34 measures continuously the pressure which is present in the feed line 10. When surpassing of a threshold value is detected in this context, the pressure sensor 34 reports the excess pressure in the feed line 10 via a sensor line 36 to the electric actuation 38 which then switches the switchover valve 14.

[0024] The invention is not limited to the aforementioned example. A person of skill in the art will have no difficulties in modifying the embodiment in a way appearing suitable to him in order to adapt it to a concrete application situation.

LIST OF REFERENCE CHARACTERS

[0025] 2 agricultural attachment [0026] 4 hydraulic pump [0027] 6 hydraulic circuit [0028] 8 tank [0029] 10 feed line [0030] 12 return line [0031] 14 switchover valve [0032] 16 pressure limiting valve [0033] 18 hydraulic motor [0034] 20 cutter bar [0035] 22 eccentric gear [0036] 24 coupling rod [0037] 26 relief opening [0038] 28 pressure actuation [0039] 30 rotational direction [0040] 32 interface [0041] 34 pressure sensor [0042] 36 sensor line [0043] 38 electrical actuation