Abstract:
A method for operating an attachment for harvesting stalk-like crops mounted on a carrier vehicle including a plurality of working tools and at least one stalk-guiding element mounted upstream from the working tools, the method including a step of causing the at least one stalk-guiding element to pivot as a function of the location or position of at least one of the attachment and the carrier vehicle.

Description:
[0001]     This application claims the benefit under 37 CFR §119(a)-(d) of German Application No. 10 2005 027 586.9 filed Jun. 14, 2005, the entirety of which is incorporated herein by reference.  
       FIELD OF THE INVENTION  
       [0002]     The invention relates to a method and a device for operating an attachment for harvesting stalk-like crops.  
       BACKGROUND OF THE INVENTION  
       [0003]     In conjunction with field choppers and their attachments, cutting and conveying devices for cutting stalk-like stem crops, such as, for example, corn, with cutting and conveying tools revolving about upright axes are known.  
         [0004]     Exemplary embodiments of a revolvingly driven cutting and conveying system of attachments for harvesting stalk-like crops are known, for example, from DE 102 805 and DE 102 30 236. These types of attachments are held on the front side of field choppers, cut off the stalk-like plants close to the ground, convey them into the draw-in shaft of the chopper.  
         [0005]     The cutting and conveying device described in DE 196 39 805 and DE 102 30 236 includes cutting and conveying rotors which are mounted next to one another transversely with respect to the direction of travel in a framework, and the conveying rotors of which have indentations which receive the cut-off stalks and retain them over a section of the revolving path and release them again in the rear region so that they can be passed on to the draw-in gap of the chopper.  
         [0006]     A cutting and conveying rotor comprises a cutting disk situated at the bottom and, situated above it on a common drive shaft, two conveying disks which are situated at a distance from each other and have indentations situated one above another. To assist the transfer of the cut-off corn stalks to the conveying disks of the conveying drums, stalk lifters with stalk-guiding elements which push the corn stalks into the indentations are mounted upstream of the cutting and conveying rotors.  
         [0007]     With increasing working widths of the attachments, the situation arises when cornering that, in the event of relatively constricted turning radii when there is a change in the direction in the working mode, the stalk lifters, guiding fingers and stem dividers are no longer oriented perpendicularly to the turning radius. As a result, when they come into contact with the plants which are still upright, they cause the stalks thereof to bend over by displacing them transversely, with the consequence that the stalk is cut off obliquely in an inclined position and the length of the stubble is thereby increased, which causes losses in the harvested crop. If this is to be avoided, a laborious turning maneuver is required, generally associated with dragging or traveling forward and backward. The present invention has set itself the object of avoiding this. Identical problems occur when working on sloping terrain if slope drift arises, and the carrier vehicle positions itself obliquely with respect to the direction of travel as a consequence of the drift forces. Even in this case, the stalk-guiding elements, which are mounted upstream of the working tools and are situated obliquely with respect to the direction of travel, tend to bend the plant stalks out of the upright position which then results in relatively long stubble lengths.  
       SUMMARY OF THE INVENTION  
       [0008]     The object of the present invention is therefore to propose a method and a device for operating an attachment having large working widths for harvesting stalk-like crops so that, even when cornering with large working widths, a uniform stubble length is obtained without causing interruption to the harvesting process. In addition, the present invention is equally suitable for drift compensation when harvesting on a slope so that uniform stubble lengths are likewise obtained therewith as on flat terrain. The present invention is thus intended to deal with both cases of use, the shortcomings of which are identical in cause, by combining solutions for both cases of use.  
         [0009]     According to the present invention, the object is achieved by the corresponding stalk-guiding elements, such as stalk lifters, guiding fingers and dividers, being automatically correspondingly readjusted with regard to their orientation with respect to the turning radius during cornering. The advantage of the present invention resides in the fact that the stalk-guiding elements, on the radius vector assigned to them, of the respective turning radius are oriented approximately or virtually perpendicularly thereto, which means that they are oriented approximately tangentially to the circumscribed circle on which the stalk-guiding elements move. The pushing transverse offset exerted on the stalks by the stalk-guiding elements mounted upstream of the cutting disks in the direction of travel as a consequence of swinging out is therefore either completely avoided, or is at least virtually, and therefore, acceptably suppressed.  
         [0010]     These orientation changes of the stalk-guiding elements are pivoting movements that take place relative to the carrier vehicle about one or more upright axes of rotation. These pivoting movements are defined by the pivot angle about precisely this pivot axis. The magnitude of the pivoting movement is indicated by the angle of inclination, and it is dependent on the amount of the turning radius being passed through at a particular instant. As an alternative, the angle of inclination may also be derived directly from the steering angle of the steering of the carrier vehicle.  
         [0011]     In the ideal case, each of the stalk-guiding elements can be pivoted separately and independently of another, in each case about its own upright pivot axis, but it is also possible for the entire attachment to be able to be pivoted relative to the carrier vehicle, so that all of the stalk-guiding elements of an attachment are pivoted about a common upright pivot axis. If the latter is the case, this is an averaged correction of the angle of inclination which, in practice, supplies sufficiently good results. However, according to the present invention, it is also possible to bring about the angle of inclination or the angles of inclination of a guiding element by means of a combination of pivoting movements such that, firstly, the entire attachment is pivoted by a partial angle of inclination relative to the carrier vehicle and, secondly, the stalk-guiding elements are pivoted individually or in groups by a further partial angle of inclination. One group of stalk-guiding fingers, as stalk-guiding elements, may be arranged, for example, on a common base of a single cutting and conveying rotor, with the result that the base can be pivoted together with the guiding elements. The sum total of both partial angles of inclination in turn produces the angle of inclination of the respective stalk-guiding element during the particular cornering operation.  
         [0012]     The angle of inclination itself is determined from the angle of lock of the steering wheels of the carrier vehicle, as is well known to the person skilled in the art, for example, from the technical teaching of automatic steering systems of carrier vehicles in the case of field choppers or combine harvesters. The value of this angle of lock is supplied to a microprocessor as an input signal from which the angle of inclination or the angles of inclination of the stalk-guiding elements is/are then calculated and supplied as a corresponding output signal to one or more actuators, which then cause the pivoting operation of the stalk-guiding elements by a corresponding angle of inclination. An actuator may be, for example, a hydraulically or an electrically actuated pivoting drive and, in a particularly advantageous manner, a hydraulic cylinder.  
         [0013]     In this case, it may be advantageous if at least one actuator is likewise equipped with a sensor which supplies conclusions concerning the state of the angle of inclination of the stalk-guiding elements, where this value is also supplied to a microprocessor as an input signal. The adjustment of the angle of inclination or angles of inclination of the stalk-guiding elements can therefore be actively assigned to the automatic steering system of the carrier vehicle in the sense of a control circuit.  
         [0014]     In the subsequent straight-ahead travel, the pivoting operation of the stalk-guiding elements is therefore neutralized again, i.e., the angles of inclination are again returned to the value zero.  
         [0015]     The particular advantage of the present invention therefore resides in the fact that at least one stalk-guiding element, as directing element, can be pivoted relative to the carrier vehicle as a function of the location or the position of the attachment. Therefore, at least one stalk-guiding element of the attachment can execute a relative rotation about a center of motion within the context of a rotation or pivoting by the amount of an angle of inclination as a consequence of a change in direction of travel of the attachment and/or of the carrier vehicle. In this case, however, the entire attachment or parts of the attachment may also participate in the pivoting. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The present invention is explained in more detail below with reference to various exemplary embodiments.  
         [0017]      FIG. 1  is a top plan view of a self-propelled harvesting machine according to the present invention.  
         [0018]      FIG. 2  is a top plan view of a harvesting implement as a self-propelled unit comprising a carrier vehicle and attachment.  
         [0019]      FIG. 3   a  is another embodiment according to the present invention.  
         [0020]      FIG. 3   b  is an enlarged detail of  FIG. 3   a.    
         [0021]      FIG. 4  is another embodiment according to the present invention.  
         [0022]      FIGS. 5   a  and  5   b  are further embodiments according to the present invention.  
         [0023]      FIG. 6  illustrates the cornering control principle with respect to the embodiment shown in  FIGS. 5   a  and  5   b.    
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]      FIG. 1  shows a self-propelled harvesting machine according to the present invention in a top plan view, including a carrier vehicle  1 , realized as a field chopper with an attachment  2  (corn picker head) which is known for harvesting entire corn plants which, after cutting and further transportation, are supplied to the draw-in gap and are drawn in by the draw-in rollers and are therefore supplied to the chopping drum. The attachment comprises a machine frame  4  with the cutting and conveying rotors  3  which are driven in a revolving manner about upright axis of rotation  8  and have cutter and conveying disks  6 ,  7  which are arranged coaxially with the axis of rotation  8  and are situated one above the other and are mounted in the machine frame  4 . The attachment is outwardly bounded by dividers  5  which are situated partly upstream from and partly next to the outer cutting and conveying rotors, and which at the same time delimit the cutting and working width  15  situated in between. Mounted upstream of the individual cutting and conveying rotors  3  are guiding fingers  9  which direct the plant stalks to be cut off into the conveying pockets of the conveying disks and push the plant stalks into them. The dividers  5  and the guiding fingers  9  therefore function as stalk-guiding elements. Guiding elements of this type also include, for example, a down crops auger or divider tips, for example on picking attachments.  
         [0025]     Carrier vehicles  1  of this self-propelled type, as illustrated in this example, generally have a rigid front axle  10 , the front wheels  11  of which are driven, and a steerable rear axle  12  situated at the center distance  16  behind the front axle  10  and having steerable rear wheels  13 . The driver&#39;s stand of the carrier vehicle is accommodated in the driver&#39;s cabin  40 .  
         [0026]     In this case, the attachment  2  is coupled to the carrier vehicle  1  in such a manner that, during cornering, it can execute pivoting movements by an angle of inclination +α or −α relative to the carrier vehicle or relative to the vertical longitudinal center plane  14  about a center of motion P, this being indicated by contour lines  17  of the pivoted attachment  2 . In this case, the center of motion P is situated at a distance  18  in front of the front axle  10 .  
         [0027]     The attachment is illustrated in  FIG. 1  in straight-ahead travel with the direction of travel F. The rear axle  12  intersects the vertical longitudinal center plane  14  of the carrier vehicle  1  at the point P 1  and the front axle  10  intersects the vertical longitudinal center plane of the carrier vehicle at the point P 2 .  
         [0028]      FIG. 2  shows the harvesting implement as a self-propelled unit, comprising the carrier vehicle  1  and the attachment  2 , during cornering with locked rear wheels  13  as the steering wheels. In principle, however, the front wheels or alternatively also both axles, i.e., both rear and front wheels, may also be steerable.  
         [0029]     The cornering, such as the left-hand cornering illustrated in  FIG. 2 , causes the carrier vehicle  1  to move about the instantaneous center of rotation M with the turning radius R. The attachment  2  therefore also moves about the instantaneous center of rotation M with the turning radius R.  
         [0030]     In order to compensate for the inclination of the stalk-guiding elements, dividers  5  and guiding fingers  9  due to the attachment  2  swinging out with respect to the direction of travel F, and in order to avoid the undesired transverse push against the plant stalks, the attachment  2  is pivoted about an upright axis of rotation, which runs through the center of motion P, by the angle of inclination α in relation to its starting position in straight-ahead travel. As a result, the longitudinal extent of the stalk-guiding elements, dividers  5  and guiding fingers  9  is now oriented with respect to the direction of travel F, by the pivoting operation with the angle of inclination α, approximately perpendicularly to the radius R″ which runs from the instantaneous center of rotation M through the center of motion P.  
         [0031]     The required angle of inclination α can be derived from the wheel locks with the angles of lock β′, β″ which are detected metrologically by angle sensors of the carrier vehicle  1 , with the angles of lock taking up a difference in angle δ with respect to each other that is caused by the turning radii on which the rear wheels  13  run differing in size. The arithmetic mean of β′ and β″ produces the angle β enclosed by the front axle  10  and the radius of the instantaneous center of rotation R which intersects point P 1 . The origin of the radius of the instantaneous center of rotation R is the instantaneous center of rotation M, with the radius vector R about the instantaneous center of rotation M describing a circular arc  19  which intersects the rear axle  12  and the vertical longitudinal center plane  14  at the point P 1 . The instantaneous center of rotation M is situated in this case approximately on the extension of the front axle  10 .  
         [0032]     Since the instantaneous center of rotation M is therefore situated with sufficient proximity on the front axle  10 , and the location of the instantaneous center of rotation P at a particular instant is therefore calculated with sufficient proximity, taking the right-angled triangle with the triangle points M, P 1 , P 2  as the basis, together with the now known angle β and the center distance  16  as follows, by the radius vector R calculated according to the relationship: 
 
sin β=center distance 16/radius of the instantaneous center of rotation  R;  
 
or 
 
radius of the instantaneous center of rotation  R =center distance 16/sin β; 
 
and therefore: 
 
cos β= R′/R;  
 
or and therefore: 
 
 R′=R ·cos β. 
 
 With the constructively defined distance  18  of the center of motion P from the front axle  10 , the required angle of inclination α can be calculated as follows: 
 
tan α=distance 18/ R ′; and 
 
α=arctan(distance 18/ R ′). 
 
         [0033]     The center of motion P therefore undergoes a change in the travel direction in relation to the straight-ahead travel by the direction of travel angle γ, which in terms of magnitude is approximately and sufficiently identical to the angle of lock α.  
         [0034]     Depending on the quadrant in which the angles of lock β′, β″ are situated, the angle α assumes a positive or negative value.  
         [0035]     It follows from this that the angle of inclination α disappears to zero if the distance  18  likewise disappears to zero, but this is not possible for cost reasons. It has therefore proven particularly favorable to dimension the distance  18  of the center of motion such that it lies within the range of 500 to 2500, preferably approximately around 1500. The center of motion P is not necessarily bound to a fixed, physical axis and may arise from a virtual axis, for example resulting from a coupling mechanism, if the attachment  2  is connected to the carrier vehicle  1  by means of coupling links. In this case, the center of motion P may also be situated upstream or downstream of the attachment  2  in the direction of travel F.  
         [0036]      FIG. 3   a  shows another embodiment according to the invention. In contrast to the embodiment according to  FIG. 2 , the entire attachment  2  is not pivoted about a common center of motion P relative to the vertical longitudinal center plane  14  during cornering. Instead, only the individual stalk-guiding elements, guiding fingers  9  and dividers  5  are pivoted relative to the carrier vehicle  1  about a respectively dedicated center of motion assigned to them. Analogously to  FIG. 2 , the center of motion P in  FIG. 3   a  is defined as a virtual pivot point P 3  which is likewise situated at the distance  18  in front of the front axle  10  and is preferably situated on the vertical longitudinal center plane  14 . The point P 3  is defined by the intersecting point of the connecting straight line  20 , on which the axes of rotation  8  of the cutting and conveying rotors  3  are situated, with the vertical longitudinal center planes  14 .  
         [0037]     Analogously to the description of the figures according to  FIG. 2 , the triangle with the triangle points M, P 2 , and P 3  now determines the average angle of inclination α about which only the stalk-guiding elements, dividers  5  and guiding fingers  9  are pivoted. The guiding fingers  5 , which are assigned to a cutting and conveying rotor  3 , are fastened, for example, to a slewing ring which is mounted below the respective cutting and conveying rotors  3  such that it can rotate about the respective axis of rotation  8 , and which can then be pivoted by the angle of inclination +α, −α by means of a suitable actuating drive. The dividers  5  may also be rotated by the angle of inclination +α, −α about an upright hinge axis  21  by means of suitable actuating drives (not illustrated). The respective center of motion about which the guiding fingers  9  of a group of a cutting and conveying rotor  3  are pivoted is, in this exemplary embodiment, particularly advantageously the axis of rotation  8  of a cutting and conveying unit  3 .  
         [0038]      FIG. 3   b  shows an enlarged detail from  FIG. 3   a  and, in addition, a coupling mechanism (illustrated in simplified form) for adjusting the direction of the guiding fingers  9  by the angle of inclination α. The guiding fingers  9  are fastened to a slewing ring  28  which is mounted below the cutting and conveying disks  3 . Fastened to the slewing ring  28  is a lever  29  which points radially outward and at the end of which is situated a point of articulation  31 . All of the points of articulation  31  are connected to a push rod  30 . The push rod  30  can be actuated by a hydraulic cylinder as actuating drive  32 , with the actuating drive  32  being clamped in the points of articulation  35  and being supported, on the one hand, on the machine frame  4  at the bracket  33  and, on the other hand, on the lever  34  of the push rod  30 . The actuating drive  32  may be coupled, for example, to a displacement transducer as angle of inclination sensor which imparts its location at a particular instant to a microprocessor onboard the carrier vehicle in the form of an input signal. In this case, the microprocessor can pass on an output signal, in the sense of a control circuit, to an actuator which controls the actuating drive  32  in such a manner that the angle of inclination α calculated at the particular instant is set at the stalk-guiding elements  9 ,  5 . In the exemplary embodiment illustrated, the four guiding fingers  9  of a cutting and conveying rotor  3  form a group of guiding fingers which, together with the slewing ring  28 , form a unit, so that they participate together in a pivoting operation with the angle of inclination α. In principle, the pivoting operation of the dividers  5  may also be connected to the coupling mechanism, with it also being entirely possible, on the other hand, for said coupling mechanism to be assigned to a separate actuating drive.  
         [0039]      FIG. 4  shows another embodiment according to the present invention. In this case, it is essentially a combination of the features of the exemplary embodiments according to  FIG. 2  and  FIGS. 3   a  and  3   b . In this exemplary embodiment, the attachment  2  is merely pivoted about part of the pivot angle α, namely by an angle of inclination λ, relative to the carrier vehicle  1 , with the stalk-guiding elements. In particular, in this use example, the guiding fingers  9  are likewise pivoted by the angle of inclination λ relative to the machine frame  4 . In a particularly advantageous manner, half of the amount of the angle of inclination α is assigned to the angle of inclination λ. In this method of controlling the cornering, it can be regarded as particularly advantageous that the pivot angles λ bisect that of the attachment  2  about the center of motion P, and of the guiding fingers  9  about the axis of rotation  8 . It is even possible to omit the pivoting of the dividers because the orientation error of the dividers  5  can then be negligibly small in practice.  
         [0040]      FIG. 5   a  and  FIG. 5   b  show yet another embodiment according to the present invention. In this exemplary embodiment, the central part  22  of the attachment  2  is coupled virtually rigidly to the carrier vehicle, i.e., is not pivotably coupled about an upright axis thereto, and as a result, the pivoting of the guiding fingers  9  of the cutting and conveying disks  3  of the central part is likewise unnecessary. Instead, during cornering, only the outer sections  23 ,  24  of the attachment  2  are pivoted through the angle of inclination α. For this purpose, it is necessary also to divide the machine frame  4  into a central part  25  and two further outer parts  26 ,  27  in which the associated cutting and conveying rotors  3  are then mounted such that they are driven in a revolving manner. During cornering, the outer sections  23 ,  24  of the attachment are pivoted about the centers of motion P 3  and P 4 , respectively, by the angle of inclination α which can be determined and calculated in accordance with the criteria set out previously.  
         [0041]     In an advantageous manner, the centers of motion P 3  and P 4  of the outer sections  23 ,  24  of the attachment are identical to the axes of rotation  8  of the cutting and conveying disks  3  situated on the outside in the central part  22  of the attachment  2 . At the same time that the sections  23 ,  24  of the attachment  2  and of the outer parts  26 ,  27  of the machine frame  4  pivot about the centers of motion P 4 , P 5 , the stalk-guiding elements, guiding fingers  9  and dividers  5  pivot by the angle of inclination α. In straight-ahead travel, as illustrated in  FIG. 5   b , the sections  23 ,  24  pivot back into their basic position, so that the amount of the angle α disappears to zero. The inventive solution according to  FIG. 5   a  and  FIG. 5   b  is particularly advantageous because, in comparison to known attachments, the central part  22  of the attachment does not require any constructive changes whatsoever, as far as the configuration of the transfer of the corn plants to the draw-in gap of the draw-in housing of the carrier vehicle  1  is concerned. Also the actuating drives  36 ,  36 ′ as pivoting drives for precisely pivoting the two outer sections  23 ,  24  by the angle of inclination α during cornering, can be realized in a particularly simple manner by means of hydraulic cylinders with identical movement control, so that the two outer sections  23 ,  24  of the attachment  2  inevitably pivot by the same amount as the angle of inclination α. In this case, the actuating drives  36 ,  36 ′ are fastened, firstly, in the point of articulation  35  of the bracket  38  on the machine frame central part  25  and, secondly, in the point of articulation  35  of the lever  39  on the respective pivotable part of the machine frame as outer part  26 ,  27 .  
         [0042]      FIG. 6  shows, with reference to the exemplary embodiment according to  FIG. 5   a  and  FIG. 5   b , the principle of cornering control according to the present invention for activating the actuating drives for pivoting the stalk-guiding elements of an attachment  2  according to the invention.  
         [0043]     The driver&#39;s control stand of the carrier vehicle  1  is situated in the driver&#39;s cabin  40 . Situated in the driver&#39;s cabin  40  is a terminal  48  with a function selection switch  61  with which the control can be preset to automatic control or to manual control.  
         [0044]     In the automatic mode, the angles of lock β′ and β″ are detected by the angle of lock sensors  44  and  45  and supplied as input signals to the input  42  of the microprocessor  41 . At the same time, the input signals of the angle of inclination sensors  45  and  46 , which detect the actual state of the angles of inclination α, are likewise applied to the input  42  of the microprocessor  41 . The software for operating the microprocessor control for controlling the cornering of the attachment is deposited in a RAM memory  60 . For the transmission of the control signals, a databus, for example an ISO bus, is provided. The actuating drives  36 ,  36 ′, realized as identical movement cylinders, are activated by the proportional directional control valves  58 ,  59 .  
         [0045]     The hydraulic unit  49  is situated onboard the carrier vehicle  1  and, on the drive side, is operatively connected to the internal combustion engine of the carrier vehicle  1  as the driving motor  51 . To minimize losses of power, on the one hand, and in particular for the purpose of providing highly dynamic cornering control on the other hand, the hydraulic pump  50  is designed as a load-sensing pump to be controlled both in terms of pressure and in terms of delivery flow.  
         [0046]     The hydraulic pump  50  is controlled via a control valve  54  based on the data recorded by a pressure sensor  55 , by a delivery flow sensor  53  and a pivot angle sensor  52 , and also as a function of the driving speed of the carrier vehicle  1 , which is detected by the speed of rotation sensor  63 , and by the angular acceleration of the adjustment speed of the angles of lock β′ β″, which is detected by the angle of lock sensors  44 ,  45 . These signals are applied to the input  42  of the microprocessor  41  as input signals. On the basis of these input signals, the microprocessor  1  determines the delivery flow required at a particular instant and the required hydrostatic pressure which the hydraulic pump has to provide for the hydraulic system so that the control operation can follow the dynamics of the cornering control.  
         [0047]     A signal for activating the control valve  54  is therefore present at the output  42  of the microprocessor, and the control valve in turn actuates the actuating drive  57  of the hydraulic pump  50  as the actuator.  
         [0048]     The pressure line  56  leads to the 4/3-way directional control valves  58 ,  59  which act on the actuating cylinders  36 ,  36 ′ on the pressure side based on the angles of lock β′ β″ that are detected metrologically by the angle of lock sensors  44 ,  45 . In the event of the actuating cylinders  36 ,  36 ′ being actuated, only one of the two actuating cylinders  36  or  36 ′ is acted upon on the pressure side by only one of the two 4/3-way directional control valves  58  or  59  being activated on the b-side, while the other one of the directional control valves  58  or  59  is activated at the same time on the a-side. The respectively displaced oil column of the activated actuating cylinder  36  or  36 ′ acts on the other actuating cylinder  36  or  36 ′ at the same time. As a consequence, if the piston rod of the one actuating cylinder, for example of the actuating cylinder  36 , is pressurized by the directional control valve  58 , it extends out of the cylinder housing, whereas the piston rod of the corresponding actuating cylinder  36 ′ retracts into the cylinder housing thereof. The displaced oil column of the actuating cylinder  36 ′ can then flow back via the directional control valve  59  that is activated on the a-side and return via the tank return line  65  into the oil tank  64  of the hydraulic unit  49 .  
         [0049]     The logic operations of this control operation are part of the software deposited in the RAM memory, with the logic evaluation and the issuing of orders being undertaken by the microprocessor  41 . This also includes the evaluation of the control logic, based on the +/− sign of the supplied data situation of the angle of lock sensors  44 ,  45  at the input  42 , which decide whether it is a left-hand or a right-hand turn and which activates the corresponding control logic. This also decides whether the directional control valve  58  is activated on the b-side, which corresponds to a left-hand turn, and, in consequence, the directional control valve  59  is activated on the a-side, or whether the directional control valve  59  is activated on the b-side and the directional control valve  58  is activated on the a-side, which corresponds to a right-hand turn.  
         [0050]     In straight-ahead travel, the two piston rods of the actuating drives  36 ,  36 ′ are in the central position, with the 4/3-way directional control valves  58 ,  59  also remaining in the central position as the locking position. A leakage oil compensation (not illustrated specifically) with a central position zero balance is also required in this connection, so that the actuating cylinders  36 ,  36 ′ cannot lose their central positions due to leakage oil losses at the seals of the piston rods during straight-ahead travel.  
         [0051]     The position of the piston rods of the actuating drives  36 ,  36 ′ at a particular instant is detected metrologically by the angle of lock sensors  45 ,  46  and the signals are supplied to the input of the microprocessor. The control of the attachment within the context of the orientation of the stalk-guiding elements, such as guiding fingers  9  and dividers  5  etc., is therefore based on an automatic microprocessor  41  controlled control circuit.  
         [0052]     As an alternative, however, the present invention also provides a manual control mode which can be preselected by the function selection switch  61 . For example, a rotary potentiometer  62  can then be used to preselect an angle of inclination +/−α which is then kept constant independently of a turn or straight-ahead travel. This is particularly an advantage on sloping terrain in order to compensate for the slope drift of the entire harvesting machine, comprising carrier vehicle  1  and attachment  2 . The stalk-guiding elements can therefore then be set on the correct course by a correspondingly set angle of inclination +/−α.  
         [0053]     The control components of the previously described steering control can be entirely accommodated, or only partially accommodated, onboard the carrier vehicle  1 , but may also be part of the attachment  2 . It is also entirely possible for a job computer to be part of the attachment  2  and for it to also be part of the steering control components, where the computer transmits its data to a microprocessor  41  of the carrier vehicle via a bus system and also receives data from the microprocessor. It is also possible for both to communicate with each other in terms of information. The bus system may be, for example, an ISO databus.  
         [0054]     The exemplary embodiments illustrated relate to the combination of field chopper as carrier vehicle  1  and attachment  2  as corn head picker. However, the present invention can also be used analogously in conjunction with other attachments, such as, for example, corn pickers and also in conjunction with other carrier vehicles  1 , such as, for example, also combine harvesters.  
         [0055]     Stalk-guiding elements of this type can therefore be guiding fingers  9 , dividers  5 , a down crops auger or divider tips.  
         [0000]     List of Designations  
         [0000]    
       
           1  Carrier vehicle (field chopper)  
           2  Attachment  
           3  Cutting and conveying rotor  
           4  Machine frame  
           5  Divider, working width limiter or guiding element  
           6  Cutter disk  
           7  Conveying disk  
           8  Axis of rotation  
           9  Guiding finger or guiding element  
           10  Front axle  
           11  Front wheels  
           12  Rear axle (steering wheels)  
           13  Rear wheels  
           14  Vertical longitudinal center plane  
           15  Cutting and working width  
           16  Center distance  
           17  Contour line  
           18  Distance  
           19  Circular arc (curved arc)  
           20  Connecting line  
           21  Upright hinge axis  
           22  Attachment central part  
           23  Attachment outer section  
           24  Attachment outer section  
           25  Machine frame central part  
           26  Machine frame outer part  
           27  Machine frame outer part  
           28  Base (slewing ring)  
           29  Lever  
           30  Push rod  
           31  Point of articulation  
           32  Actuating drive (hydraulic cylinder)  
           33  Bracket  
           34  Lever  
           35  Point of articulation  
           36 ,  36 ′ Actuating drive (hydraulic cylinder)  
           37  Point of articulation  
           38  Bracket  
           39  Lever  
           40  Driver&#39;s cabin  
           41  Microprocessor  
           42  Inputs microprocessor  
           43  Outputs microprocessor  
           44  Angle of lock sensor  
           45  Angle of lock sensor  
           46  Angle of inclination sensor  
           47  Angle of inclination sensor  
           48  Terminal  
           49  Hydraulic unit  
           50  Hydraulic pump  
           51  Driving motor  
           52  Pivot angle sensor  
           53  Delivery flow sensor  
           54  Control valve  
           55  Pressure sensor  
           56  Pressure line  
           57  Actuating drive  
           58  Directional control valve  
           59  Directional control valve  
           60  RAM memory  
           61  Function selection switch  
           62  Rotary potentiometer  
           63  Speed of rotation sensor  
           64  Oil tank  
           65  Tank return  
           66  Control device  
           67  Job computer  
          F Direction of travel  
          M Instantaneous center of rotation  
          P Center of motion  
          P 1  Intersecting point  
          P 2  Intersecting point  
          P 3  Intersecting point  
          P 4  Center of motion  
          P 5  Center of motion  
          R Radius of the instantaneous center of rotation  
          R′ Radius component  
          R″ Radius  
          α Angle of inclination  
          β Averaged angle of lock  
          β′ Angle of lock  
          β″ Angle of lock  
          γ Direction of travel angle  
          δ Difference in angle  
          λ Angle of inclination