The invention relates to an agricultural device for processing crop which lies loosely on the ground, for example mowed grass, which agricultural device comprises a trailer which can be coupled to a tractor, which trailer is provided with:

- an undercarriage having a central longitudinal axis, which undercarriage is provided with:

• a coupling member for coupling to a tractor,

· a plurality of wheels by means of which the undercarriage can travel on the ground,

- a crop-processing device which is provided with:

• a tilting frame which is connected to the undercarriage so as to be tiltable about a tilting axis which runs substantially transversely with respect to the longitudinal axis of the undercarriage,

• two supporting arms which extend on either side of the tilting frame, which supporting arms are each connected to the tilting frame so as to be pivotable about a swivel axis which runs substantially transversely with respect to the tilting axis, and which supporting arms each comprise a plurality of supporting arm portions which are connected to each other so as to be hingable about hinge axes which run substantially parallel to the swivel axis of said supporting arm,

• crop-processing members which are fitted to the supporting arm portions of the supporting arms so as to be rotatable,

wherein the crop-processing device is movable from a transport position to an operating position, wherein,

in the transport position, the tilting frame has a raised position in which the swivel axes of the supporting arms run substantially vertically, and each supporting arm has a collapsed position, in which said supporting arm runs substantially parallel to the longitudinal axis of the undercarriage, and

when moving the crop-processing device from the transport position to the operating position, each supporting arm is swung outwards about the swivel axis thereof, from the collapsed position into an extended position, in which said supporting arm extends outwards substantially transversely with respect to the longitudinal axis of the undercarriage, and subsequently the tilting frame is tilted downwards about the tilting axis, from the raised position to a lowered position, in which the crop-processing members are oriented for processing crop which is lying loosely on the ground, in which case the operating position has been reached. The agricultural device according to the invention is, for example, a tedder.

NL 1031852 discloses a tedder. Said tedder comprises a trailer with an undercarriage and a crop-processing device. The undercarriage has a central longitudinal axis which corresponds to the direction of travel of the tedder. The undercarriage comprises a drawbar which is connectable to a tractor, and two wheels which can travel on the ground. A tilting frame is connected to the undercarriage via a hydraulic lifting cylinder so as to be tiltable about a tilting axis which runs substantially transversely with respect to the longitudinal axis of the undercarriage. Supporting arms are present on either side of the tilting frame, which supporting arms are each connected to the tilting frame via hydraulic extension cylinders so as to be pivotable about a swivel axis which runs substantially transversely with respect to the tilting axis. Each supporting arm is composed of a plurality of supporting arm portions which are connected to each other so as to be hingable about hinge axes which run substantially parallel to the swivel axis of said supporting arm. Sets of wheels with rotatable crop-processing members are attached to the supporting arm portions.

The crop-processing device is movable between a transport position and an operating position. In the transport position, the tilting frame is in a raised position, in which the swivel axes of the supporting arms run substantially vertically. In the transport position, the supporting arms each have a collapsed position in which the supporting arms each run substantially parallel to the longitudinal axis of the undercarriage. In order to move the crop-processing device from the transport position to the operating position, each supporting arm is swung outwards by means of the associated hydraulic extension cylinder about the swivel axis thereof into an extended position, in which said supporting arm extends outwards substantially transversely with respect to the longitudinal axis of the undercarriage. In the collapsed position of the supporting arms, the centre of gravity of the crop-processing device, i.e. the tilting frame with the supporting arms and rotatable crop-processing members connected thereto, are in a position, viewed in the direction of the longitudinal axis, in front of the tilting axis of the tilting frame. When extending the supporting arms, i.e. swinging the supporting arms into the extended position by means of the extension cylinders, the centre of gravity of the tilting frame with the supporting arms and rotatable crop-processing members connected thereto is, again viewed in the direction of the longitudinal axis, meant to be moved beyond the tilting axis (dead point position) to a position behind the latter. In this case, the tilting frame with the supporting arms and rotatable crop- processing members connected thereto descends into the operating position on account of its own weight.

However, if the supporting arms are swung outwards from the collapsed position, one or more supporting arm portions may remain in a slightly forwardly tilted position. As a result thereof, there is a risk, when moving the crop- processing device from the transport position to the operating position, of the centre of gravity of the combination of tilting frame, supporting arms and crop- processing members, viewed in the direction of the longitudinal axis, remaining situated in front of the tilting axis of the tilting frame. This means that when the supporting arms are being extended, the crop-processing device does not move through the dead point position and therefore does not descend into the operation position on account of its own weight. In this case, for example, the driver of the tractor has to get out and manually pull the supporting arm portions backwards in order to cause the crop-processing device to move through the dead point and into the operating position. However, this is time-consuming and laborious.

It is an object of the invention to provide an improved agricultural device.

This object is achieved according to the invention by the fact that each supporting arm is provided with at least one actuating member which is arranged between two adjacent supporting arm portions of said supporting arm which are hingably connected to each other and the actuating members are configured to bring and/or keep said supporting arm portions of each supporting arm substantially in line with each other while the supporting arms are being swung outwards from the collapsed position to the extended position, in such a manner that the centre of gravity of the crop-processing device, in the extended position of the supporting arms, viewed in the direction of the longitudinal axis of the undercarriage, is situated behind the tilting axis and the crop-processing device descends into the operating position on account of its own weight.

According to the invention, in the transport position, the supporting arms are each swung inwards about the swivel axis thereof into the collapsed position, i.e. the supporting arms are folded in and run approximately parallel to the longitudinal axis of the undercarriage. In the collapsed position, the supporting arms rest on, for example, supports of the undercarriage of the trailer. In order to move the crop-processing device into the operating position, the supporting arms are in this case first lifted from the supports and subsequently swung outwards until they reach the extended position. According to the invention, the actuating members are actuated while the supporting arms are being extended. The actuating members are arranged between adjacent supporting arm portions of the supporting arms which are hingably connected to each other. According to the invention, said supporting arm portions are therefore pushed apart/away from each other by the actuating members, i.e. said supporting arm portions hinge with respect to each other in such a way that said supporting arm portions come to lie substantially in line with each other and/or are kept in said orientation. As a result thereof, the actuating members prevent the supporting arm portions from remaining tilted forwards when the supporting arms are being extended. It is thus ensured, when swinging the supporting arms outwards, that the centre of gravity of the crop-processing device, viewed in the direction of the longitudinal axis of the undercarriage, moves from a position in front of the tilting axis, past the tilting axis, and to a position behind the tilting axis. In other words, when the supporting arms are being extended, the centre of gravity of the combination of tilting frame, supporting arms and crop-processing members is moved, viewed in the direction of the longitudinal axis, through the dead point position until it is situated behind the tilting axis, so that the crop-processing device descends into the operating position on account of its own weight. According to the invention, the crop- processing device can therefore be brought into the operating position in a reliable manner.

According to the invention, it is preferred if the actuating members each comprise a hydraulic cylinder. The use of hydraulic cylinders is advantageous with regard to the reliability and service life of the agricultural device. In this case, it is possible for each of the hydraulic cylinders to be single- acting.

In a preferred embodiment, each actuating member is configured in such a manner that the hinged connection between the two hingably connected supporting arm portions between which said actuating member is arranged is released by said actuating member in the operating position of the crop- processing device. If each of the actuating members is configured as a hydraulic cylinder, each hydraulic cylinder is pressurized when the supporting arms are being extended and the pressure is removed in the operating position of the crop- processing device. In this case, the hydraulic cylinders are therefore pressure cylinders.

Each of the supporting arms comprises a number of supporting arm portions which are hingably connected to each other about hinge axes which extend substantially parallel to the swivel axis of said supporting arm. In the operating position of the crop-processing device, said hinge axes run substantially parallel to the longitudinal axis of the undercarriage, i.e. substantially in the direction of travel. The actuating members are arranged between in each case two adjacent supporting arm portions which are hingably connected to each other. The actuating members are configured to bring and/or keep said supporting arm portions substantially in line with each other while the supporting arms are swung outwards from the collapsed position to the extended position, i.e. the actuating members are actuated when the supporting arms are being extended. As has been explained above, this ensures that the crop-processing device moves through the dead point position and descends into the operating position on account of its own weight after the supporting arms have been extended. Once the crop-processing device has been moved past the dead point position during extension of the supporting arms, the actuating members can be released or de- actuated. In practice, the release of the actuating members is, for example, carried out after the operating position has been reached. In the operating position, the supporting arm portions can pivot freely and substantially unimpeded by the actuating members with respect to each other in order to follow the ground. Therefore, the operation of the agricultural device in the operating position is hardly influenced by the released actuating members, if at all. In an embodiment according to the invention, an actuating member is arranged between an outer supporting arm portion and an adjacent supporting arm portion of each supporting arm. The expression outer supporting arm portion is understood to mean the supporting arm portion on the free end of the supporting arm which protrudes outwards furthest in the extended position. If the supporting arm portions of the supporting arms do not remain in line during extension of the supporting arms, the outer supporting arm portions tilt forward furthest. The actuating members according to the invention are particularly efficient if they are arranged between the outer supporting arm portions and the adjacent supporting arm portions. This makes it possible to influence the position of the centre of gravity of the crop-processing device relatively significantly.

In this case, it is possible for each supporting arm to comprise a second actuating member which is arranged between two supporting arm portions which are situated between, on one side, the outer supporting arm portion and the adjacent supporting arm portion and, on the other side, the swivel axis of said supporting arm. In this case, each supporting arm comprises two actuating members. The first actuating member is arranged between the outer supporting arm portion and the adjacent supporting arm portion, while the second actuating member is situated further inwards with respect thereto. This is particularly advantageous with a crop-processing device having relatively long supporting arms, for example if the operating width of the crop-processing device is 12.5 metres or more.

In an embodiment according to the invention, the supporting arms can each be positioned between the collapsed position and the extended position thereof by in each case a double-acting hydraulic extension cylinder. The hydraulic extension cylinders are each connected between the tilting frame and the respective supporting arms. The hydraulic extension cylinders are configured to be double-acting, so that the supporting arms can each be moved from the collapsed position to the extended position and back. The hydraulic extension cylinders can be operated in a reliable and simple manner.

According to the invention, the tilting frame can be moved from the lowered position to the raised position by a hydraulic lifting cylinder. According to the invention, the tilting frame descends from the raised position to the lowered position on account of the weight of the crop-processing device, so that the operating position is reached. In order to move the crop-processing device back from the operating position to the transport position, the tilting frame is first raised from the lowered position to the raised position by the hydraulic lifting cylinder. Subsequently, the supporting arms are collapsed into the collapsed position. The crop-processing device is then in the transport position.

The hydraulic lifting cylinder may be configured in different ways. For example, the hydraulic lifting cylinder is single-acting. According to the invention, it is also possible for the hydraulic lifting cylinder to be provided with a piston having a single-acting striker portion and a double-acting striker portion which is smaller than the single-acting striker portion. For example, the single-acting striker portion is smaller than 20% or smaller than 10% or even smaller than 5% of the double- acting striker portion. Such a hydraulic lifting cylinder may be configured as described in NL 1036540.

Using a hydraulic lifting cylinder with single-acting/double-acting functionality, it is possible to provide the undercarriage with two supports for supporting the respective supporting arms in the transport position of the crop- processing device, and wherein

the crop-processing device is movable from the transport position to the operating position by:

· raising each of the supporting arms, from the transport position, from the supports by moving the piston of the lifting cylinder in a first direction over the double-acting striker portion, wherein the tilting frame is tilted from the raised position to a raised intermediate position, in which the swivel axes of the supporting arms still run substantially vertically, and · subsequently swinging each of the supporting arms from the collapsed position to the extended position, and

• thereafter tilting the tilting frame from the raised intermediate position downwards into the lowered position on account of the own weight of the crop-processing device, wherein the piston of the lifting cylinder is carried along in the first direction over the single-acting striker portion, and

the crop-processing device is movable from the operating position to the transport position by: • tilting the tilting frame upwards until it is in the raised intermediate position by driving the piston of the lifting cylinder in a second direction, counter to the first direction, over the single-acting striker portion, and

• subsequently swinging each of the supporting arms from the extended position to the collapsed position, and

• thereafter lowering each of the supporting arms onto the supports by moving the piston of the lifting cylinder in the second direction over the double-acting striker portion, wherein the tilting frame is tilted from the raised intermediate position into the raised position.

As a result thereof, it is possible to lock the supporting arms safely and reliably in the transport position, while the supporting arms can readily be raised slightly from the transport position and then be expanded in order to move the crop-processing device to the operating position. When the crop-processing device is returned to the transport position, the supporting arms in the collapsed position initially remain suspended slightly over the supports, following which the supporting arms can be laid in a slow and controlled manner on the supports when the piston is moved in the second direction over the small double-acting stroke.

The invention also relates to a method for processing crop which is lying loosely on the ground, for example mowed grass, wherein use is made of an agricultural device which comprises a trailer, which trailer can be coupled to a tractor and is provided with:

- an undercarriage having a central longitudinal axis, which undercarriage is provided with:

• a coupling member for coupling to a tractor,

· a plurality of wheels by means of which the undercarriage can travel on the ground,

- a crop-processing device which is provided with:

• a tilting frame which is connected to the undercarriage so as to be tiltable about a tilting axis which runs substantially transversely with respect to the longitudinal axis of the undercarriage,

• two supporting arms which extend on either side of the tilting frame, which supporting arms are each connected to the tilting frame so as to be pivotable about a swivel axis which runs substantially transversely with respect to the tilting axis, and which supporting arms each comprise a plurality of supporting arm portions which are connected to each other to as to be hingable about hinge axes which run substantially parallel to the swivel axis of said supporting arm,

· crop-processing members which are rotatably arranged on the supporting arm portions of the supporting arms, wherein the method comprises:

- moving the crop-processing device from a transport position to an operating position, wherein,

in the transport position, the tilting frame has a raised position in which the swivel axes of the supporting arms run substantially vertically, and each supporting arm has a collapsed position, in which said supporting arm runs substantially parallel to the longitudinal axis of the undercarriage, and

when moving the crop-processing device from the transport position to the operating position, swinging each supporting arm outwards about the swivel axis thereof from the collapsed position into an extended position, in which said supporting arm extends outwards substantially transversely with respect to the longitudinal axis of the undercarriage, and subsequently tilting the tilting frame downwards about the tilting axis from the raised position to a lowered position, in which the crop-processing members are oriented for processing crop which is lying loosely on the ground, in which case the operating position has been reached,

wherein

each supporting arm is provided with at least one actuating member which is arranged between two adjacent supporting arm portions of said supporting arm which are hingably connected to each other, and said supporting arm portions of each supporting arm are brought and/or kept substantially in line with each other while the supporting arms are being swung outwards from the collapsed position to the extended position, in such a manner that the centre of gravity of the crop- processing device, in the extended position of the supporting arms, viewed in the direction of the longitudinal axis of the undercarriage, is situated behind the tilting axis and the crop-processing device descends into the operating position on account of its own weight. In this case, it is preferable if each of the actuating members comprises a hydraulic cylinder which is configured, for example, as a single-acting cylinder. The method according to the invention preferably comprises processing the crop which is lying loosely on the ground by the crop-processing members in the operating position of the crop-processing device, wherein each actuating member is configured in such a manner that the hinged connection between the two hingably connected supporting arm portions between which said actuating member is arranged is released by said actuating member in the operating position of the crop-processing device. As a result thereof, the crop-processing members can readily follow the ground during use.

The invention will now be explained in more detail with reference to an exemplary embodiment which is illustrated in the figures.

Figure 1 a shows a top view of an agricultural device according to the invention, wherein the crop-processing device is in the transport position.

Figure 1 b shows a top view of the agricultural device illustrated in Figure 1 a, wherein the supporting arms are swung outwards into the extended position, while the tilting frame has not yet been tilted downwards.

Figure 1 c shows a top view of the agricultural device illustrated in Figure 1 a, wherein the crop-processing device is in the operating position.

Figure 2a shows a side view of the agricultural device illustrated in Figure

1 a, wherein the crop-processing device is in the transport position.

Figure 2b shows a side view of the agricultural device illustrated in Figure 1 a, wherein the crop-processing device is in the operating position.

Figure 2c shows a side view of the agricultural device illustrated in Figure 1 a, wherein the crop-processing device is in the turning position.

Figure 3a shows a rear view of the agricultural device illustrated in Figure 1 a, wherein the crop-processing device is in the transport position.

Figure 3b shows a rear view of the agricultural device illustrated in Figure 1 a, wherein the crop-processing device is in the turning position.

Figure 4 shows a cross-sectional view of the hydraulic lifting cylinder of the agricultural device illustrated in Figure 1 a.

The agricultural device for processing crop which is lying loosely on the ground 4, for example mowed grass, is denoted in the figures by reference numeral 1. In this exemplary embodiment, the agricultural device 1 forms a tedder. The tedder 1 comprises a trailer 2 which is provided with an undercarriage 3 and a crop-processing device 8.

At its front end, the undercarriage 3 comprises a drawbar 6 which can be coupled to a tractor (not shown). The undercarriage 3 comprises a central beam which defines a central longitudinal axis 5 of the undercarriage 3. In this exemplary embodiment, the undercarriage 3 comprises two wheels 7 by means of which the trailer 2 is movable on the ground 4. The undercarriage 3 comprises two supports 40 which protrude transversely with respect to the central beam.

The crop-processing device 8 comprises a tilting frame 9 which is connected to a rear end of the undercarriage 3 so as to be tiltable about a tilting axis 19 which runs substantially transversely with respect to the longitudinal axis 5 of the undercarriage 3. Between the tilting frame 9 and the undercarriage 3, a hydraulic lifting cylinder 10 is arranged, which is shown in more detail in Figure 4.

At the end 1 1 which is shown on the right-hand side in Figure 4, the hydraulic lifting cylinder 10 is connected to the undercarriage 3. At the opposite end 1 1 , a piston rod 14 of the lifting cylinder 10 is connected to the tilting frame 9. The lifting cylinder 10 comprises a cylinder housing 12, in which a piston 13 is accommodated so as to be able to move in a reciprocating manner. On either side of the piston 13, respective chambers 15, 16 are formed. Via openings 17A, 17B in the cylinder housing 12, hydraulic liquid can be supplied to or discharged from the chambers 15, 16. Piston rod 14 which extends in chamber 16 is attached to the piston 13.

An elongate shut-off body 18 is arranged in the opening 17A which is in fluid communication with the chamber 15. The shut-off body 18 comprises a pin- shaped part 18B and a widened section 18A which is connected thereto. The pin- shaped part 18B is accommodated in a through-opening 15A which opens into the chamber 15. The widened section 18A has a ring-shaped shoulder surface which faces the piston 13.

When hydraulic liquid is supplied to the opening 17A, said liquid leaks past the widened section 18A, and said liquid then flows past the pin-shaped part 18B via the through-opening 15A into the chamber 15. At the same time, the shut-off body 18 moves on account of the hydraulic pressure in the direction towards the piston 13, in Figure 4 to the left, until the ring-shaped shoulder surface of the widened section 18A closes off the through-opening. The piston 13 can then still move further in the direction away from the shut-off body 18, in Figure 4 to the left, as will be explained below.

As long as the through-opening 15A is in fluid communication with the opening 17A, the hydraulic lifting cylinder 10 is double-acting. As soon as the through-opening 15A is closed off by the shut-off body 18, the hydraulic lifting cylinder 10 becomes single-acting. The piston 13 of the hydraulic lifting cylinder 10 illustrated in Figure 4 therefore comprises a single-acting striker portion which is determined by the stroke of the piston 13 which corresponds to the stroke of the shut-off body 18, and a double-acting striker portion which is determined by the remaining stroke of the piston 13 after the through-opening 15A has been closed off by the shut-off body 18. In this exemplary embodiment, the double-acting striker portion is significantly smaller than the single-acting striker portion.

Two supporting arms 20, 21 extend on either side of the tilting frame 9. The supporting arms 20, 21 are each connected to the tilting frame 9 so as to be pivotable about a swivel axis 22, 23 which runs substantially transversely with respect to the tilting axis 19. The supporting arms 20, 21 each comprise a plurality of supporting arm portions 24, 24A which are connected to each other so as to be hingable about hinge axes 25 which run substantially parallel to the swivel axis 22, 23 of the associated supporting arm 20, 21 . Hydraulic extension cylinders 32 are arranged between the tilting frame 9 and the supporting arm portions 24 which are connected thereto.

The supporting arm portions 24, 24A are provided with crop- processing members 26 which are rotatable about rotation axes 27 (see Figure 2b). In this exemplary embodiment, two rotatable crop-processing members 26 are also fitted to the tilting frame 9. The crop-processing members 26 have sets of wheels 28 for resting on the ground 4. The crop-processing members 26 each comprise a plurality of teeth 29 in order to process crop which is lying loosely on the ground 4.

The crop-processing device 8 is movable between a transport position and an operating position, i.e. from the transport position to the operating position and back again. The transport position is illustrated in Figures 1 a, 2a, 3a, while the operating position is shown in Figures 1 c and 2b. Now, moving the crop- processing device 8 between the transport position and the operating position according to the invention will be described. In the transport position, each supporting arm 20, 21 is in a collapsed position, in which said supporting arm 20, 21 runs substantially parallel to the longitudinal axis 5 of the undercarriage 3. In this case, the supporting arms 20, 21 are accommodated in the supports 40. In the transport position, the tilting frame 9 has a raised position, in which the swivel axes 22, 23 of the supporting arms 20, 21 run substantially vertical. In the transport position, the agricultural device 1 can be driven on public roads using a tractor.

Each of the supporting arms 20, 21 is raised from the supports 40 out of the transport position over a small height by supplying hydraulic liquid via a line (not shown) to the opening 17A of the lifting cylinder 10. As a result of the hydraulic pressure, the piston 13 in Figure 4 moves to the left until the shut-off body 18 closes off the through-opening to the chamber 15. The piston 13 is thus moved over the distance which corresponds to the double-acting striker portion. As a result thereof, the tilting frame 9 is tilted through a small angle from the raised position to a raised intermediate position, in which the swivel axes 22, 23 of the supporting arms 20, 21 still run substantially vertical.

Subsequently, the line to the opening 17A is closed, after which each of the supporting arms 20, 21 is extended from the collapsed position about the swivel axes 22, 23 until they reach an extended position by means of the extension cylinders 32. In the extended position of the supporting arms 20, 21 , said supporting arms 20, 21 extend outwards substantially transversely with respect to the longitudinal axis 5 of the undercarriage 3.

In this exemplary embodiment, each supporting arm 20, 21 comprises two hydraulic pressure cylinders 31 which are each arranged between two adjacent supporting arm portions 24, 24A of said supporting arm 20, 21 which are hingably connected to each other. The first pressure cylinder 31 is arranged between an outer supporting arm portion 24A and an adjacent supporting arm portion 24 of each supporting arm 20, 21 . The second pressure cylinder 31 is connected between two other supporting arm portions 24 which are situated further inwards. According to the invention, it is also possible to use different actuating members instead of hydraulic pressure cylinders.

The pressure cylinders 31 are configured to bring and/or keep the supporting arm portions 24, 24A of each supporting arm 20, 21 substantially in line with each other when the supporting arms 20, 21 are being swung outwards from the collapsed position to the extended position. Due to the fact that the pressure cylinders 31 prevent the supporting arm portions 24, 24A from remaining in a forwardly tilted position, it is ensured that the centre of gravity Z of the crop- processing device 8, viewed in the direction of the longitudinal axis 5 of the undercarriage 3, moves from a position in front of the tilting axis 19, past the tilting axis 19 to a position behind the tilting axis 19. In other words, in the extended position of the supporting arms 20, 21 , the centre of gravity Z of the crop- processing device 8, viewed in the direction of the longitudinal axis 5 of the undercarriage 3, is situated behind the tilting axis 19.

This means that the crop-processing device 8 moves down on account of its own weight when the supporting arms 20, 21 are being extended. In this case, the piston 13 of the lifting cylinder 10 is carried along - the piston 13 in Figure 4 is consequently moved further to the left over a distance corresponding to the single-acting striker portion. Since the line to the opening 17A still remains closed, the chamber 15 will be evacuated. On account of the own weight of the crop-processing device 8, the tilting frame 9 therefore moves from the raised intermediate position to a lowered position, thus reaching the operating position.

In the operating position, the crop-processing members 26 are arranged for processing the crop which is lying loosely on the ground 4. In this case, the pressure cylinders 31 are opened, so that the supporting arm portions 24, 24A can pivot freely with respect to each other and substantially unimpeded by the pressure cylinders 31 . As a result thereof, the crop-processing members 26 can follow the ground 4 well in the operating position.

In order to move the crop-processing device 8 back to the transport position from the operating position, the hydraulic lifting cylinder 10 is first operated. Via the opening 17B, hydraulic liquid is supplied to the chamber 16 (see Figure 4), so that the piston 13 of the lifting cylinder 10 in Figure 1 moves to the right over the distance which corresponds to the single-acting striker portion. In this case, the vacuum in the chamber 15 is released. Since the line to the opening 17A is still closed, the piston 13 cannot move further than the single-acting striker portion. In this case, the hydraulic liquid present in the chamber 15 is compressed between the piston 13 and the shut-off body 18 which closes off the through- opening 15A. From the lowered position, the tilting frame 9 therefore tilts upwards and back into the raised intermediate position. Subsequently, each of the supporting arms 20, 21 is swung from the extended position to the collapsed position by means of the extension cylinders 32. Only then is the line to the opening 17A opened, so that the hydraulic liquid can flow out of the chamber 15. As a result thereof, the piston 13 of the lifting cylinder 10 can move further, in Figure 4 towards the right, over the distance which corresponds to the double-acting striker portion. In this case, the tilting frame 9 tilts from the raised intermediate position to the raised position, so that the supporting arms 20, 21 are lowered together onto the supports 40 relatively slowly. In this way, the transport position is reached again.

As is illustrated in Figures 2c and 3b, the crop-processing device 8 can also be moved to a turning position by operating the hydraulic lifting cylinder 10. The turning position is situated between the transport position and the operating position.

The invention is not limited to the exemplary embodiment illustrated in the figures. The person skilled in the art may carry out various modifications which are within the scope of the invention. In particular, any feature from the description may, both separately and in any conceivable combination, be used in one or more of the characterizing clauses of the claims.