DE20117874U1 - Hay tedder, comprising specific arrangement of rods and levers for precise steering, particularly on smaller areas - Google Patents

Abstract

The hay tedder (1), comprising several rotating spreading devices (5, 5A) joined to swivel mounted bars (22, 22A), and two wheels (7, 7A) at both sides of a transversal axle (6), is attached to and pulled by a tractor (2). A combined pushing and pulling rod (8), positioned parallel to the central shaft (4) is swivel mounted to the towing unit (3) with its front end and to a return lever (13) with its rear end. A hydraulic cylinder (23) is joined between the return lever (13) and the steering device (12) acting on the steering levers (25, 25A) moving the wheels (7, 7A). When the pushing and pulling rod (8) is moved the steering levers (25, 25A) are moved simultaneously driving the wheels (7, 7A) into the appropriate direction.

Description

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NIEMEYER Agricultural Machinery GmbH 05. November 2001

PO Box 11 65 Ba./Av

48466 Hoerstel

Haymaking machine

&iacgr;&ogr; The invention relates to a rotary rake with at least two rake rotors according to the generic term of claim 1.

EP 0 316 896 B1 describes a haymaking machine, in particular a rotary swather with a steering device that makes it possible to control the wheels of the wheel carrier of the chassis, which are supported so as to pivot about vertical axes, depending on the pivoting of the attachment relative to the drawbar by means of a push and pull rod and corresponding tie rods. The attachment is the coupling link between the tractor and the drawbar of the rotary swather, with the attachment and drawbar being coupled to one another so as to pivot about a vertical axis. The push and pull rod is connected in an articulated manner to the attachment on the one hand and to the tie rods of the wheels on the other hand by means of an angle lever that is mounted on the wheel carrier around a vertical axis. By changing the direction of travel of the tractor and the pivoting of the attachment, a change in angle occurs between the attachment and the drawbar, whereby this change in angle is used as a control variable for the steering process. The transmission of this control variable takes place through the articulated coupling of the pull and push rod with the angle lever, which in turn functions as a steering column, and which in turn is articulatedly coupled to the tie rods and the steering levers of the wheels, so that the control variable angle changes

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when cornering, pushing or pulling forces are exerted on the push and pull rod, which leads to displacements, i.e. changes in the position of the push and pull rod. This causes the steering column to pivot around its vertical axis, and this pivoting simultaneously leads to displacements of the articulated tie rod, which leads to the wheels pivoting around their vertical axes, whereby the steering angle of the tractor is indirectly transferred to the wheels of the rotary swather.

&iacgr;&ogr; EP 1 095 556 A1 describes a haymaking machine, in particular a rotary swather, whose steering properties are improved compared to EP 0 316 896 B1. The improved steering properties are achieved by the type of linkage of the tie rod to the angle lever, designed as a steering column. This is achieved by the steering rods, in their alignment transverse to the direction of travel, occupying a common spatial overlap area, which means that the steering angles of the wheels when cornering are adapted to the respective rolling radii as far as possible.

The invention aims to further optimize the steering behavior, especially in the context of enabling the smallest possible curve radii. However, the smallest possible curve radii require the largest possible steering angle in relation to the tractor and drawbar and also the largest possible steering angle in relation to the drawbar and the wheels.

This requirement is of economic importance, as even smaller grassland areas are being worked by increasingly powerful rotary rakes. In order to achieve the smallest possible curves when turning right or left, it is particularly important that the steering mechanism of the wheels is positioned in relation to the direction of travel in the

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Straight-line driving is constructed with exact mirror symmetry. Even small deviations from this mirror symmetry of the steering device lead to significant differences in the curve radii when cornering tightly, due to the rolling behavior of the wheels. Adequate rolling behavior of the wheels must be ensured, i.e. unstable rolling conditions must be avoided, as this could otherwise lead to the wheels skidding and this could damage the grass hub.

&iacgr;&ogr; In particularly tight headlands, the option of manoeuvring backwards would also be a great advantage, provided that the current turning maneuver that has already been initiated and partially carried out still makes this sensible. This is because in this maneuvering state, the wheels may already have moved into a very unfavorable steering position, which would mean that the steering angle between the drawbar and the tractor would be increased even further for the intended reversing, and could lead the tractor and implement into a critical state with the risk of breakage. This state could then only be overcome by driving forwards with the front wheels of the tractor steering in the opposite direction in order to bring about an opposite steering angle between the tractor and the drawbar, which would then completely contradict the intended steering maneuver.

The object of the invention is therefore to create a rotary rake of the generic type with improved steering properties, which enables improved maneuverability on the headland.

This object is achieved with the features of the characterizing part of claim 1. Further advantages and embodiments according to the invention are the

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following description, drawings and claims 2 to 6.

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shows:

Fig. 1 - A rotary rake according to the invention driving straight ahead in a plan view of the working plane.

Fig. 1a-A partial view of the rear part of the rotary rake in an enlarged view.

Fig. 2 - A rotary rake according to the invention in a left-hand curve in a plan view of the working plane.

Fig. 3 - A rotary rake according to the invention in a right-hand bend in a plan view of the working plane.

Fig. 4 - A rotary rake according to the invention driving straight ahead in a plan view of the working plane with hydraulic steering assistance.

Fig. 4a- A section through an embodiment of a hydraulic actuator for steering assistance.

Fig. 4b A partial view of the rear part of the rotary rake 1 according to Fig.4 in an enlarged representation.

Fig. 5 - A rotary rake according to the invention in a left-hand bend in a plan view of the working plane with a steering assistance in neutral position in a forward drive.

Fig. 6 - A rotary rake according to the invention in the starting position of a left-hand bend in a plan view of the working plane with a

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Steering assistance for reversing, with corrected wheel position.

Fig. 6a - A partial view of the rear part of the rotary rake 1 according to Fig.6 in an enlarged representation.

Fig. 7 - A rotary rake according to the invention in the starting position of a right-hand bend in a top view of the working plane with a steering support for reversing, with corrected &iacgr;&ogr; impeller position

Fig. 7a - A partial view of the rear part of the rotary rake 1 according to Fig.7 in an enlarged representation.

In Fig. 1, a rotary swather 1 according to the invention is shown in a simplified form in a plan view of the working plane, traveling straight ahead in the direction of travel F. The rotary swather 1 is coupled in a known manner to the coupling points of the lower links of a tractor 2 by means of an attachment 3. A side swather is shown as a possible embodiment of a rotary swather 1. It essentially consists of the attachment 3, the drawbar 4, which is pivotally connected to the attachment 3 at the articulation point 28 about the vertical axis 9, the rake rotors 5,5' with the directions of rotation 27,27', whereby each rake rotor 5,5' is supported on the ground in a known manner by means of feeler and support wheels, the booms 22,22' on which the rake rotors are pivotally connected to the drawbar 4 about folding axes 24,24' parallel to the direction of travel from their working position to the transport position and vice versa, and a machine cross member 6 on which the running wheels 7,7' are pivotally mounted about vertical axes 20,20'.

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The steering device consists of a link chain. This essentially consists of the push and pull rods 8, reversing lever 13, coupling link 23, steering column 12, tie rods 19,19' and steering levers 25,25'. The individual links of this link chain are operatively connected to one another as follows:

The push and pull rod 8 is connected on the one hand to the attachment part 3 at the articulation point 14 and on the other hand to the bell crank 13 at the articulation point 15, whereby the bell crank 13 is pivoted in a bell crank bearing 29 about a vertical axis

11 is pivotably supported on the drawbar. The reversing lever 13 is connected at the pivot point 16 to the coupling member 23 and thus at the pivot point 17 to the steering column 12, whereby the steering column 12 is supported in the pivot bearing 30 on the machine cross member 6 so as to be pivotable about a vertical axis 10. The steering column 12 is connected at the pivot points 18,18' to the tie rods 19,19' and at the pivot points 21,21' to the steering levers 25,25'. The steering levers 25,25' are pivotably but non-rotatably connected to the respective running wheel 7,7' and are supported about their vertical axis 20,20' on the machine cross member 6 in the pivot bearings 31,31'. In the illustrated embodiment, the coupling member 23 is designed as a simple non-length-adjustable tension and compression member, i.e. merely as a push and pull rod.

Displacements of the push and pull rod 8, which are coupled to pivoting movements of the attachment 3 about its vertical axis 9 in the articulation point 28, cause - thus also displacements of the tie rods 19,19', whereby actuating forces inevitably become effective in the articulation points 21,21' on the steering levers 25,25' and act on them. This has the consequence that the wheels 7,7' are forced to change direction.

In Fig. 1a, a partial view of the rear part of the rotary swather 1 according to Fig. 1 is shown enlarged. The deflection lever 13, which is located in front of the steering column 12, enables the thrust and

Tie rod 8 independent reorientation of the downstream structural design of the steering column 12, the position of the articulation points 15,16,17 18,18*21,21' including the position and alignment and geometry of the tie rods 19,19' and the steering levers 25,25'. The exact mirror-image structure of the steering column geometry in connection with the spatial overlap of the tie rods 19,19', the distance dimension 26,26' and the exactly equal overlap angles ß,ß' is of particular importance for the same curve radii in extremely tight cornering when cornering left and right.

Fig. 2 shows a left turn of the rotary swather 1 with the steering angle α between the longitudinal axis of the tractor and the longitudinal alignment of the drawbar 4 and Fig. 3 shows a right turn of the rotary swather 1 with the steering angle α'. In practice, the steering angle α, α' should be able to reach at least 75° without the support wheels starting to skid.

In Fig. 4, a rotary swather 1 according to the invention is shown in a plan view of the working plane, traveling straight ahead, with additional hydraulic steering assistance. This steering assistance consists in the coupling member 23 according to Fig. 1 being designed, for example, as a hydraulically actuated, i.e. pressurized fluid-loaded, length-adjustable actuator. This actuator 32 can, for example, be designed as a differential cylinder and be actuated from the control unit of a tractor 2. In a particularly advantageous manner, however, the actuator 32 can be formed by two differential cylinders connected in series, which also represent a structural unit.

In Fig. 4a, such a structural unit of two differential cylinders connected in series is shown in section to form an actuator 32. Two differential cylinders 33, 33' face each other on the bottom side and are rigidly

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with their cylinder housings 34,34' connected to one another by an intermediate wall 38 in such a way that the center line 39 of both piston rods 35,35' lie on a common axis. The rigid connection of both differential cylinders 33,33' can, for example, be particularly advantageously realized by a welded connection 36. The particular advantage of this design of a hydraulically actuated actuator 32 is that both differential cylinders 33,33' lying in a line of action can be actuated independently of one another and the end positions of both piston rods 35,35' can be controlled independently of additional control elements of the end position control Î, which causes several defined control states, as explained further below.

Fig. 4b shows an enlarged partial view of the rear part of the rotary swather 1 according to Fig. 4. The piston rods 35, 35' thus emerge from the respective interior of the differential cylinders 33, 33' through the two outlet openings of the cylinder housings 34, 34' facing away from one another, with the free ends of the piston rods 35, 35' being designed as hinge eyes 37, 37'. These hinge eyes 37, 37' are then attached to the hinge points 16, 17 of the link chain of the steering device. This illustration shows the tractor and rotary swather driving straight ahead as a team. The piston rod 35 of the differential cylinder 33 is on the block, i.e. completely retracted into the cylinder housing 34 as far as the stop, and the piston rod 35' of the differential cylinder. 33' on block, i.e. completely extended to the stop "out" of the cylinder housing 34'. This defined position of the actuator 32 thus indicates straight-ahead travel and thus the neutral position of the actuator 32.

The differential cylinders 33,33' can, for example, be controlled, i.e. operated, independently of one another by a control unit on the tractor side.

Alternatively, for example, it is also possible to control electromagnetically operated directional control valves mounted on the device, whereby

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These are connected to the on-board hydraulics of the tractor 2 in a known manner with plug-in couplings and the control itself can be carried out, for example, via a control panel on the tractor side.

Fig. 5 shows a rotary swather 1 according to the invention in a left-hand bend in a top view of the working plane with steering assistance in the neutral position in a forward drive. The actuator 32 is also in the neutral position according to the figure description in Fig. 4 or Fig. 4b.

In Fig. 6, a rotary swather 1 according to the invention is shown in the starting position of a left-hand bend in a top view of the working plane with steering support for reversing, with corrected running wheel position, and in Fig. 6a, a partial view of the rear part of the rotary swather 1 according to Fig. 6 is shown enlarged. In order to prevent the situation described above of an imminent risk of breakage when reversing, the running wheels 7, 7' were pivoted by means of the actuator 32 of the hydraulic steering support before reversing the team against the position of the running wheels 7, 7' created by cornering. In the case shown, this pivoting takes place by actuating the differential cylinder 33 by extending the piston rod 35. As a result, during reversing in the marked direction of travel F, the drawbar 4 now pivots in the completely opposite pivoting direction around the vertical axis 9 in the articulation point 28, which would not have been possible without the steering correction. This prevents the drawbar from pivoting further in the wrong direction, which would have increased the steering angle α and could have resulted in a risk of breakage of the tractor or implement.

In Fig. 7 and Fig. 7a, the same situation is described as shown in Fig. 6 and Fig. 6a, but from the position of a right-hand bend

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out. In this case, too, a steering correction for reversing is shown. In this case, the steering correction is carried out by moving the piston rod 35' into the differential cylinder 33' in relation to its neutral position, which now causes the wheels to pivot in the opposite direction.

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List of reference symbols

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1 - Rotary rake 30 - Articulated stick bearing 2- tractor 31,31'- Swivel bearing 5 3- Attachment 32 Actuator A- Drawbar 33,33' Differential cylinder 5.5'- gyroscopic 34,34' Cylinder housing 6- Machine cross member 35.35' Piston rods 7,T- Wheels 36 Welded joint 10 8th- Push and pull rod 37,37' Joint eyes 9- Vertical axis 38- Partition wall 10- Vertical axis 39- Centerline 11 - Vertical axis ^2r Steering column 15 13- reversing lever 14- Articulation point 15- Articulation point 16- Articulation point 17- Articulation point 20 18,18'- Articulation point 19,19'- Tie rods 20,20' - Vertical axis 21,21'- Articulation point 22,22' - boom 25 23- Coupling link 24,24' - Folding axis 25.25' - Steering lever 27,27' - Direction of rotation F- Direction of travel 28- Articulation point &agr;,&agr;'- Steering angle 30 29 - Bellows bearing ß,ß'- Coverage angle

Claims (6)

1. Haymaking machine, in particular rotary swather ( 1 ) with at least two rake rotors ( 5 , 5 ') arranged next to one another transversely to the direction of travel (F) of the machine and supported on the ground by means of feeler and support wheels, a machine cross member ( 6 ) connected at its ends to the rake rotors ( 5 , 5 '), which has a machine cross member ( 6 ) connected to a rigid drawbar ( 4 ) that can be connected to an agricultural towing vehicle, for example a tractor ( 2 ), and two booms ( 22 , 22') that can each be folded up about a folding axis ( 24 , 24 ') parallel to the direction of travel, on which the rake rotors ( 5 , 5 ') are arranged, with two booms ( 22 , 22 ') arranged parallel and next to one another at a distance behind the machine cross member ( 6 ), which can be pivoted and steerable running wheels ( 7 , 7 ') which are supported on the ground and which can be steered by a steering device depending on changes in alignment between the drawbar ( 4 ) and the tractor ( 2 ), and the steering movements of the running wheels ( 7 , 7 '), which are each articulated to a steering column ( 12 ) by means of a steering lever ( 25 , 25 ') and a tie rod ( 19 , 19 '), are brought about by controlled pivoting movements of the steering column ( 12 ), characterized in that the articulated chain of the steering device is extended in such a way that a deflection lever ( 13 ) is mounted in front of the steering column ( 12 ), to which the push and pull rod ( 8 ) is attached on the one hand in the articulation point ( 15 ) and on the other hand a coupling member ( 23 ) is attached in the articulation point ( 16 ). 2. Rotary swather according to claim 1, characterized in that the coupling member ( 23 ) is designed as a push and pull rod. 3. Rotary swather according to claim 1, characterized in that the coupling member ( 23 ) is designed as a length-adjustable actuator. 4. Rotary swather according to claim 3, characterized in that the length-adjustable actuator is designed as a hydraulic cylinder pressurized with pressure fluid. 5. Rotary rake according to claim 4, characterized in that the hydraulic cylinder acted upon by pressure fluid consists of two differential cylinders ( 33 , 33 ') connected in series. 6. Rotary swather according to claim 1, characterized in that the distance dimensions ( 26 , 26 ') between the vertical axis ( 20 ) of the running wheel ( 7 ) and the vertical axis ( 10 ) of the steering column ( 12 ) or between the vertical axis ( 20 ') of the running wheel ( 7 ') and the vertical axis ( 10 ) of the steering column ( 12 ) and the overlap angles (β, β') and the tie rods ( 19 , 19 ') are equal to one another.