Abstract:
A forage harvester header is coupled to a forage harvester and is equipped with at least one mower and intake drive assembly for cutting crop and transporting the cut crop to a discharge conveyor which delivers the crop to a feed channel of the forage harvester. The drive arrangement for the header is such that the velocity of the discharge conveyor can be varied relative to the velocity of the mower and intake drive assembly.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention concerns a header attachable to a forage harvester for mowing crops to be harvested, which crops have having stalks, and with at least one mower and intake drive assembly for the mowing and transporting away of harvested crop and a discharge conveyer to which harvested crop can be conducted from the mower and intake drive assembly and that is arranged to conduct the crop to the intake channel of the forage harvester, where the speed of the discharge conveyor can be varied relative to the speed of the mower and intake drive assembly.  
       BACKGROUND OF THE INVENTION  
       [0002]     Headers for mowing crops having stalks so as to be harvested are used in combination with self-propelled, towed or attached forage harvesters for the total plant harvest, for example, for the harvest of silage corn. A commonly used type of such a header is described in EP 0 760 200A. The header of this publication includes a number of mower and intake drive assemblies arranged alongside each other for the mowing and transporting away of the plants along whose rear side the harvested crop is conducted to the center of the header. There it is conveyed to the rear into the intake channel of the forage harvester by means of discharge conveyors in the form of so-called slope conveyor drums which rotate about generally vertical axes which, however are inclined slightly in the forward direction, where the crop is compressed by rough pressing rolls and conducted to a chopper drum. The latter chops the harvested crop and conducts it to a blower that conveys the harvested crop from the forage harvester to a transport vehicle. The mower and intake drive assemblies and the discharge conveyors are connected with an output drive of the forage harvester over gearboxes with fixed speed ratios. 
        for a variation of the length of cut, the usual practice is to vary the rotational speed of the rough pressing rolls of the forage harvester, that can be performed by means of shifted gearboxes, adjustable hydraulic drives (for example, see WO 02/056672 A) or combined mechanical-hydraulic drives (WO 99/48353 A). At that point, the rotational speed of the chop[per drum remains approximately constant, so that the length of cut is inversely proportional to the rotational speed and the velocity of the rough pressing rolls.        
 
         [0004]     At the present time, a trend towards longer lengths of cut can be observed. The longer lengths of cut require a relatively high velocity for the rough pressing rolls. In order to avoid problems in the transport during the transition of the plants from the discharge conveyor of the header to the rough pressing rolls of the forage harvester, caused by difference in speed, there is the possibility of also operating al driven elements of the header at higher rotational speeds. For this purpose, multi-speed shifted gearboxes are used. It has also been proposed that the front harvesting attachment be driven at a speed proportional to the rotational speed of the rough pressing rolls (WO 99/48353 A). The disadvantage in a variation of the rotational speeds of all driven elements of the header is seen in the fact that the rotational speeds of the mower and intake drive assemblies are also increased, although that speed increase does not bring about any improvement in the conveying of the harvested crop and hence is not necessary. It increases the power requirement of the drive and results in increased wear of the cutting knives and the braking arrangements of the header.  
         [0005]     WO 02/056672 A describes a forage harvester with a header for mowing crops to be harvested, in which the slope conveyor drums are driven at a speed that is independent of the speed of the mower and intake drive assemblies. For this purpose, the rough pressing rolls and the slope conveyor drums are driven together by a first hydraulic motor while the remaining driven elements of the header are driven by a second hydraulic motor. Here the disadvantage is seen in the fact that two drive connections must be provided between the forage harvester and the header, that is, between the slope conveyor drums and the first hydraulic motor as well as between the remaining driven elements of the header and the second hydraulic motor. Thereby, the attachment and removal of the header to or from the forage harvester is rather time consuming. Furthermore, the efficiency of the hydraulic rives is relatively poor.  
         [0006]     EP 1 055 359 A proposes that a transverse screw conveyor or transverse conveyor bands of a cutter head for a combine be driven hydraulically at an adjustable speed, while the beam of the cutter head is driven mechanically. The reel is driven hydraulically, at a fixed rotational speed. Here, too, a number of hydraulic drives with limited efficiency are provided.  
         [0007]     The problem underlying the invention is seen in the need to make available a machine for harvesting crops having stalks that is improved over the aforementioned state of the art in which the velocity of the discharge conveyor is made to conform to the rotational speed of the rough pressing rolls of the forage harvester.  
       SUMMARY OF THE INVENTION  
       [0008]     According to the present invention, there is provided an improved drive for parts of a forage harvester header.  
         [0009]     An object of the invention is to provide a drive for parts of a forage harvester header wherein the rotational speed of the discharge conveyor is variable.  
         [0010]     In this way, the velocity of the discharge conveyor can be made to conform to the velocity of the rough pressing rolls by a variation in the speed ration of the gearbox without great cost. The speed of the mower and intake drive assembly is not changed, thereby unnecessary wear and higher drive power demand of the mower and intake drive assembly is no longer required. The discharge conveyor, in particular, is a slope conveyor drum that rotates about a generally vertical axis inclined slightly in the forward direction, in order to overcome the differences in height between the header and the forage harvester, or it is a transverse screw conveyor.  
         [0011]     With the use of a gearbox with variable transmission ration, it is sufficient to establish a single drive connection between the machine and the forage harvester. This drive connection drives a shaft that drives the mower and intake drive assembly as well as the discharge conveyor. Moreover, there is the possibility of equipping the machine with several shafts that are driven by separate drive connections from the forage harvester, each of which drives one or more mower and intake drive assembly and in each case drives a discharge conveyor through a gearbox with variable transmission ratio. In other embodiments, it would also be conceivable that the gearbox with variable transmission ration be driven by the forage harvester separate from the drive of the mower and intake drive assemblies.  
         [0012]     Preferably, the mower and intake drive assembly is driven by a completely mechanical drive-line from an internal combustion engine used as the main drive power of the forage harvester, that is, avoiding hydraulic drive components that are subject to power losses. Thereby, the result is a rotational speed of the mower and intake drive assembly that is proportional to the rotational speed of the internal combustion engine. Since the latter is usually constant, the rotational speed of the mower and intake drive assembly also remains constant.  
         [0013]     The gearbox with variable transmission ration is seen primarily in the form of a mechanical gearbox, for example as shifted gearbox, in which various speed rations can be selected, in which a selection is made which pair of meshing gears from among a series of such meshing gears ins inserted into the drive-line. Alternatively, a gearbox that is operated as continuously variable without steps can be used, such as a variable speed belt drive. A hydraulic drive could also be used with a pump and a motor. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The drawings show an embodiment of the invention that is described in further detail in the following.  
         [0015]      FIG. 1  shows a schematic side view of a forage harvester with a header for mowing crops having stalks being harvested.  
         [0016]      FIG. 2  shows a plan view of the header and the rough pressing rolls of the forage harvester.  
         [0017]      FIG. 3  shows a plan view of the drive-line of the forage harvester and header. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     A self-propelled forage harvester  10 , as shown in  FIG. 1 , is supported on a frame  12  that is carried by driven front wheels and steerable rear wheels  14  and  16 . The forage harvester  10  is controlled from an operator&#39;s cab  18  from which a header  20  for mowing crops to be harvested can be viewed. Crop taken up from the ground by means of the header  20 , for example, corn, grass or the like is conducted to a chopper drum  22  by lower rough pressing rolls  30 ,  32  and upper rough pressing rolls  34 ,  36  arranged in an intake channel of the harvesting machine  10 . The chopper drum  22  chops the crop into small pieces and delivers it to a conveyor arrangement  24 . As a rule, the upper rough pressing rolls  34 ,  36  are arranged so that they can move relative to the lower intake rolls  30 , 32  and are forced against the latter by spring force. The crop leaves the harvesting machine  10  to an accompanying trailer over a duct  26  mounted for being selectively rotated about an upright axis. A post chopper reduction arrangement  28  is arranged between the chopper drum  22  and the conveyor arrangement  24  through which crop to be conveyed is conducted tangentially to the conveyor arrangement  24 , the post chopper reduction arrangement  28  is composed of two processing rolls arranged one above the other.  
         [0019]      FIG. 2  is a plan view of the header  20  in which the rough pressing rolls  34 ,  36  are also shown schematically. Te header  20  is provided with a transverse support carrier that is composed of a central segment  38  connected with the intake channel of the forage harvester  10  and tow outer segments  40  that can be pivoted upward for transport on public roads by a hydraulic cylinder about an axis extending parallel to the forward operating direction V. Eight mower and intake drive assemblies  42  are supported side-by-side alongside each other on the transverse carrier. Any desired other quantity of mower and intake drive assemblies  42  could also be used. The mower and intake drive assemblies  42  are provided with lower cutter disks and conveyor disks arranged above the lower cutter disks and include recesses distributed about their circumference which engage plant stalks. These are preceded by larger stalk dividers  44  and smaller stalk dividers  46  arranged between them.  
         [0020]     Transverse conveyor drums  50  are located on the rear side of the gore regions between adjoining mower and intake drive assemblies  42  (except for the region between the mower and intake drive assemblies  42 ′ which is bisected by the longitudinal center plane  48 , and the region between each of the outer intake and drive assemblies  42 ″ and the adjacent drive assembly  42 ). Each of the outer mower and intake drive assemblies  42  rotates in the opposite direction from the three mower and intake drive assemblies  42 ,  42  and  42 ″ following inward from each drive assembly  42 ″, so that transverse conveyor drums  50  can be omitted downstream of the outer mower and intake drive assemblies  42 ″. Discharge conveyors  52  are located on the rear sides of the mower and intake drive assemblies  42 ′ adjoining the longitudinal center plane  48 , the discharge conveyors being configured in the form of so-called slop conveyor drums with approximately vertical axes of rotation inclined slightly in the forward direction, these are used to overcome the difference in height between the floor of the header  20  and the intake channel of the forage harvester  10 .  
         [0021]     During harvester operation, the mower and intake drive assemblies  42 ,  42 ′ and  42 ″ rotate in the directions indicated by the arrows and separate the crop to be harvested from the ground by means of their cutter disks and engage the crop in the recesses of their conveyor disks. The crop is then transported in the direction of the longitudinal center plane  48  of the header  20  along their rear sides by the transverse conveyor drum  50  interacting with the rear sides of the mower and intake drive assemblies  42 ,  42 ′ and  42 ″. Then the crop is taken over by the discharge conveyors  52  that convey the crop at first in the direction towards the longitudinal center plane  48  and then to the rear and upward into the intake channel of the forage harvester  10 . Since the header shown here and its operation has been described in greater detail, for example, in EP 0 760 200 A, whose disclosure is incorporated into the present document by reference, further explanation of the operation is omitted here.  
         [0022]      FIG. 3  shows the drive-line of the header  20  and of the forage harvester  10 . An internal combustion engine  54  drives a belt  58  by means of a belt pulley  56 , the belt interacts with a belt pulley  60  that drives the conveyor arrangement  24  and a conveyor disk  62 , which drives the chopper drum  22 . The chopper drum  22  in turn drives a shaft  64  which drives a belt pulley  66 . The belt pulley  66  is connected so as to drive a belt pulley  70  by means of a belt  68 , the belt pulley  70  drives the input shaft  74  of a length of cut gearbox  72 . Alternatively, a drive connection with gears is provided between the chopper drum  22  and the length of cut gear box  72 .  
         [0023]     The length of cut gear box  72  contains drive elements that drive the rough pressing rolls  30 - 36 . The rotational speed of the rough pressing rolls  30 - 36  can be varied continuously or in steps by the length of cut gearbox  72 . Preferably, a length of cut gearbox is applied here, such as is described by WO 99/48353 A, that is it contains a planetary gear set which is provided with mechanically and hydraulically driven elements, in order to make available the rotational speed of the rough pressing rolls  30 - 36  primarily mechanically and in order to be able to vary the speed hydraulically. However, a purely hydraulic drive of the rough pressing rolls  30 - 36  is conceivable.  
         [0024]     The length of cut gear box  72  transmits the drive energy from the internal combustion engine  54  purely mechanically to the stub shaft  76  to which a removable articulated shaft  7  of variable or fixed length is fastened. Here, a rotational speed transmission can be performed. The articulated shaft  78  extends from the stub shaft  76  of the length of cut gearbox  72  to a stub shaft  80  of an input gearbox  82  of the header  20 . The input gearbox  82  is connected so as to drive by means of gears and/or chains, not shown, with a transverse shaft  84  which is located within the segments  38 ,  40  of the transverse carrier and that extends generally over the entire width of the header  20 . In the transition region to the segments  40  that can be folded upward, appropriate clutches (not shown) are provided in the transverse shaft  84 . The transverse shaft  84  drives by means of bevel gears (not shown) or the like eight gearboxes  86 , each of which is associated with a mower and intake drive assembly  42 . The transverse shaft  84  is connected so as to drive the transverse conveyor drums  50  by means of four further, smaller gearboxes  88 . Finally, the transverse shaft  84  drives a shift gearbox  90 , that is configured as a shift gearbox with a variable transmission ration. ON its output side, the shift gearbox  90  drives the discharge conveyor  52 , shown at the right in  FIG. 2 , and a shaft  92 , which in turn drives a further gearbox  94  that again in turn drives the discharge conveyor  52 , shown at the left in  FIG. 2 . An actuator  96 , that can be remotely controlled electrically or hydraulically by an operator in the operator&#39;s cab  18 , permits a change in the speed transmission of the shift gearbox  90 . In a possible embodiment, a two-step gearbox  90  permits a variation in the rotational speed of the discharge conveyors  52  by approximately 10%. The shift gearbox  90  may be a mechanical gearbox that is provided with two or more pairs of meshing gears of differing diameter. In each case, one of the pair of gears is brought into driving connection with a shaft by a movable coupling member.  
         [0025]     In other embodiments, two transverse shafts  84  are provided, each of which extends approximately to the longitudinal center plane  48  and are driven by associated articulated shafts  78  from both sides of the intake channel. Then, the drive of the gearbox  94  can be performed, as shown in the drawing, or from the transverse shaft  84  of the left half of the header  20 , as shown by  FIG. 3 ; then, it must also be configured as a shift gearbox  90  and the shaft  92  can be omitted. In place of the relatively small mower and intake drive assemblies  42 ,  42 ′ and  42 ″ shown, whose diameter amounts to approximately 75 cm., larger mower and intake drive drums could also be used. An endless conveyor cold also be applied here, as described in DE 199 51 636 A.  
         [0026]     The length of cut gearbox  72  permits a variation in the rotational speed of the rough pressing rolls  30 - 36  within a certain range of the length of cut. The rotational speed of the mower and intake drive assemblies  42 ,  42 ′ and  42 ″, and the trans verse conveyor drums  50  that are driven by the internal combustion engine  54  over the purely mechanical drive line, as described, is independent of the rotational speed of the rough pressing rolls  30 - 36  at a constant rotational speed of the internal combustion engine  54 . This speed is selected in such a way that a safe cut of the stalk crop to be harvested, particularly corn, and a trouble-free transport of the harvested crop to the discharge conveyor  52  can be assured. At larger lengths of cut that correspond to higher rotational speeds of the rough pressing rolls  30 - 36 , the speed of the discharge conveyors  52  can be increased by means of the shift gearbox  90 , which improves the transport of the harvested crop in this region. In case that smaller lengths of cut are demanded, the rotational speed of the discharge conveyor  52  can again be reduced analogously.  
         [0027]     During reverse operation, that can be performed by means of a reversing motor of the length of cut gearbox  72 , or a hydraulic motor at that location used to change the length of cut, the driven elements of the header  20  rotate in the opposite direction.  
         [0028]     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.