Abstract:
An agricultural harvesting machine for removing and separating grain from harvested crop has a threshing zone and at least one separation zone for separating the grain. The axial separating rotor is at least partially encased by a separating housing having a plurality of sections. At least one of the sections is displaceable in the axial direction of the at least one axial separating rotor to increase the opening and ensure separation when a correspondingly large proportion of grain are in the outer region of the rotating crop stream and the proportion of admixtures is small.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The invention relates generally to the field of agricultural machinery and, more specifically, to an agricultural machine having apparatus for separating grain from harvested crop. 
     DESCRIPTION OF THE RELATED ART 
     A combine harvesting machine having a single-cylinder or multi-cylinder threshing mechanism in a rear region is disclosed in EP 0 591 688. The single-cylinder or multi-cylinder threshing mechanism is associated with one or two axial separating rotors, respectively, along a longitudinal direction of the combine harvester. Each of the axial separating rotors has a rotating rotor therein which is provided with entraining elements at its circumference and which, at least in its bottom region, cooperates with a separating grate fixed to the frame and at least partially encasing the rotor. At the top, the rotor is enclosed by enveloping surfaces in such a way that between the rotor, the separating grate and these enveloping surfaces is formed a through-gap through which the agricultural crop is conveyed in spiral paths along the rotor axis by the axial separating rotor. During this conveying process, separation of the grain and straw mixture conveyed by the axial separating rotor occurs, wherein grains, short straw and chaff are separated by the openings formed in the separating grates. In the front region of the axial separating rotor, a considerable proportion of short straw and chaff, so-called impurities, is separated, as the grains which are in the crop stream must first be conveyed by the action of centrifugal force into an outer edge region of the crop stream before they can be separated in the region of the separating grates. To facilitate separation of admixtures, intensive cleaning of the separated crop mixture is required. The cleaning systems are provided for this purpose and mounted behind the axial separating rotor in the agricultural harvesting machine. When there is a considerable proportion of admixtures, the cleaning systems installed on the agricultural harvesting machine are not sufficient to achieve the required purity of crop. As such, the crop must be further cleaned in stationary cleaning devices. This leads to considerable extra expenditure, which greatly increases the costs of the harvesting process. 
     U.S. Pat. No. 4,869,272 discloses an axial-flow combine harvester having an axial-flow threshing and separating rotor with a rotatable rotor about its longitudinal axis. EP 0 591 688, discloses a rotor having dual functions of threshing and separating the grain from the harvested crop conveyed by the rotor. For this purpose, a front region of the rotor is the threshing zone and an adjoining rear region of the rotor is a separating zone. Both the threshing zone and the separating zone are enveloped at the top by shell surfaces. In the lower region of the rotor, the shell surfaces merge with concaves and separating grates for separating grain from straw mixture. At the beginning of the separating zone, the grains embedded in the crop stream are first moved into an outer region of the spiraling, rotating crop stream before they can pass through the openings of the separating grates. In axial-flow combine harvesters, this leads to a considerably higher proportion of admixtures being separated at the beginning of the separating zone, resulting in overloading the subsequent cleaning components. 
     The present invention is directed to overcome one or more of the problems as set forth above. 
     SUMMARY OF THE INVENTION 
     In one aspect of this invention, an agricultural harvesting machine having means for removing and separating grain from the harvested crop such that the harvested crop separated in the separating zones has a reduced proportion of admixtures. 
     In another aspect of the present invention, there is an agricultural harvesting machine for removing and separating grain from harvested crop, comprising, a threshing zone having threshing members for threshing crop; at least one separating zone having at least one axial separating rotor partially encased by a separating surface and operatively connected to the threshing zone for receiving the threshed crop from the threshing zone and for separating the grain, wherein sections of the separating zone are displaceable in the axial direction of the at least one axial separating rotor; means for separating the grain from the harvested crop; and means for removing the grain from the threshed crop, wherein at least the removal and partial preliminary separation of the grain from the threshed crop take place in the threshing zone. 
     In yet another aspect of the invention, the separation zone has a separating surface operatively connected to the at least one axial separating rotor, wherein the separating zone has sections which can be displaced in the axial direction of the at least one axial separating rotor to ensure that separation will not begin until a correspondingly large proportion of grains are arranged in an outer region of a rotating crop stream, so that the proportion of admixtures separated by the axial separating rotor remains small. 
     In still another aspect of the invention, displacement of sections of the separating zone is obtained by encasing the axial separating rotor in a separating surface and by at least partially closing the axial separating rotor with the separating surface. 
     In yet another aspect of the invention, a particularly advantageous effect of the invention is obtained if the axial separating rotor associated with a tangential threshing mechanism or the separating zone of an axial-flow threshing and separating rotor is constructed in the manner according to the invention. 
     In another aspect of the invention, the separating surface is segmented and the segments are pivotable to an open and closed position, wherein the separating surface is closed successively beginning in a crop entry region of the separating surface, and opened in the reverse order. 
     In another aspect of the invention, the separating surface holds, in the circumferential direction of the at least one axial separating rotor, a plurality of pivotable closure flaps. Each of the closure flaps are independently controlled and can close a portion of the separating surface, but in cooperation with closure flaps adjacent to it allows complete covering of the separating surface. In this way, it is ensured that each closure flap need only a small area for pivoting between its opened and closed positions, hence saving space. 
     In an aspect of the invention, there are closure flaps arranged in an axial direction of the axial separating rotor, so that displacement of sections in a front region of the separating zone is achieved in a structurally simple manner. 
     In another aspect of the invention, closure flaps are arranged adjacent to each other in a circumferential direction of the axial separating rotor and are pivotably connected to each other by a coupling member, so that a single displacing operation pivots all of the closure flaps that are operatively connected to each other simultaneously. 
     To simplify displacement of the closure flaps, the closure flaps arranged adjacent to each other in the circumferential direction of the axial separating rotor can be pivotably connected to each other by a coupling member, so that a single displacing operation pivots all the closure flaps connected to each other simultaneously. 
     In still another aspect of the invention, the closure flaps are opened and closed such that the closure flaps are arranged one behind the other and operatively and pivotably connected to each other by a common pivot mechanism. 
     In yet another aspect of the invention, there are closure flaps that are successively opened and closed by coupling members. The closure flaps move along slot guides that have curved paths, wherein the shape of the curved paths ensures that closing of the closure flaps begins at the beginning of the axial separating rotor and opening of the closure flaps begins with the closure flaps closest to the rotor end. The axial displacement is effected by displacement means known in the art, which are operatively connected to the slot guides by at least one coupling rod. 
     An aspect of the invention is slot guides pivotably arranged about a shaft pointing in the axial direction of the at least one axial separating rotor, wherein the shape of the slot guides ensure the order of opening and closing of the closure flaps. The arrangement of the slot guides can lead to a considerable reduction of displacement paths hence a space savings. 
     In another aspect of the invention, closure flaps are the displacement means, and the closure flaps are independent of each other and actuated independently of each other to achieve flexible displacement capacities. 
     In still another aspect of the invention, the agricultural machine has a plurality of axial separating rotors, displacement means and associated displacement mechanisms, wherein the displacement mechanism is arranged in a gap between the axial separating rotors to reduce the particles swirling around said gap. 
     In yet another aspect of the invention, the crop passing through the separating surface is not hindered in its movement by the closure flaps. Further, adjacent closure flaps can have such a pivot range that when in their opened position, they form the shape of a funnel opening in a radial direction. 
     In another aspect of the invention, displacement of sections in a front region of the separating zone facilitates separation of admixtures and depends on crop properties such as moisture, fracture behaviour, grain size. The displacement varies as a function of the separation of admixtures in the front region of the separating zone. 
     An aspect of the invention is achieved by displacing sections in a front region of the separating zone, wherein displacement is effected automatically as a function of the separation of admixtures. Sensors sense the proportion of admixtures, and a control and evaluation unit receive the sensed signal and use said signal to control the through flow of admixtures and to correct the through flow via opening or closing closure flaps. 
     The above aspects are merely illustrative and should not be construed as all-inclusive and limiting to the scope of the invention. The aspects and advantages of the present invention will become apparent, as it becomes better understood from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is now made more particularly to the drawings which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views. 
     FIG. 1 is a side view of a combine harvester having a tangential threshing mechanism and axial separating rotor; 
     FIG. 2 is a cross-sectional view through line II—II of FIG. 1 with closure flaps located in an open position; 
     FIG. 3 is a cross-sectional view taken generally along line II—II of FIG. 1 with closure flaps located in a closed position; 
     FIG. 4 is a detailed view of an axial separating rotor as shown in FIG. 1; 
     FIG. 5 is a side view of a combine harvester having an axial threshing and separating rotor; and 
     FIG. 6 is a cross-sectional view like FIG. 3, but illustrating an alternative embodiment of a pivot mechanism. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows an agricultural harvesting machine in the form of a combine harvester  1 . The combine harvester  1  has a feed rake  3  at a front region as determined from the direction of travel FR when harvesting crop. As seen in FIG. 1, the feed rake  3  rotates counterclockwise as shown by arrows  4 . Conveyor  5  transfers the harvested crop in a crop stream  6  from the feed rake  3  to a multi-cylinder threshing mechanism  7 . The threshing mechanism  7  has threshing cylinders  9 ,  10 , which rotate counterclockwise as shown by arrow  8 . The threshing cylinders  9 ,  10  pick up and convey the crop stream  6  along concaves  11 ,  12  toward a feed roller  13 . During the movement of the crop stream  6 , grains are removed from the ears and at least partially separated on the concaves  11 ,  12  and delivered to subsequent working components. In a rear region of the threshing mechanism  7 , the crop stream  6  is picked up by the feed roller  13  and delivered to an input region  14  of an axial separating device  15  arranged at an incline in the direction of the travel FR. It is contemplated that the multi-cylinder threshing mechanism  7  shown can be replaced by a single-cylinder threshing mechanism (not shown), and instead of the axial separating device  15  being a single-rotor, a twin-rotor or multi-rotor axial separating device  15   a ,  15   b  as shown in FIG. 2 can be mounted behind the threshing mechanism  7 . Each of the axial separating devices  15   a ,  15   b  has an axial separating rotor  18 . These rotors counter rotate as shown by arrows  16 ,  17 . The axial separating devices  15   a ,  15   b  have circumferential surfaces  19  encompassed by entraining elements  20  of a shape capable of wrapping around the circumferential surfaces  19  in spiral form. Each of the axial separating rotors  18  is encased by a cover  21  at a top region. The covers  21  are operatively attached to mounting rails at its lower region, which releasably hold frame structures  23  of any convenient design. In a manner known in the art, the frame structures  23  are releasably attached to and hold a separating surface  25 . The separating surface has through-openings  24 . As shown in FIG. 4, the separating surface  25  are preferably a plurality of segments  26 - 29  which are operatively connected to the frame structure  23  forming a separating grate  30 . In the combine harvester  1  shown in FIG. 1, the multi-cylinder threshing machine  7  defines a threshing zone  31  and the axial separating device  15  defines a separating zone  32 . 
     As shown in FIGS. 2 and 3, first and a second segment  29 ,  28 , respectively, of the separating surface  25  have closure flaps  33 . The closure flaps  33  are spaced apart in the circumferential direction of the axial separating rotor  18 . The closure flaps  33  are attached to the frame structure  23  of the separating grate  30  at a first end so as to be pivotable about shafts  35  extending in a axial direction  34  of the axial separating rotor  18 . A sealing surface  36  is operatively attached or integral with each of the closure flaps  33 . Spaced from the sealing surface  36  is an axially-extending pivot shaft  37 . Each of the pivot shafts  37  is conveniently held non-rotatable by an arcuate coupling member  38 , wherein the arcuate coupling member  38  non-rotatably holds one or more guide bolts  39 . FIG. 4 shows first reinforcing struts  40  centrally associated with each of the front segments  28 ,  29  of the separating surface  25 . The first reinforcing struts  40  are laterally and integrally formed. As shown in FIG. 3, second reinforcing struts  41  have slot guides  42 . The slot guides  42  engage the guide bolts  39  formed integrally with the coupling members  38 , so that the coupling members  38  can perform a pivot movement as shown by arrow  43  about the associated regions of the separating surface  25 . The movement is dependent upon the length of the slot guides  42 . The arcuate coupling members  38  are pivotably about and traversed to bolts  44 . The bolts  44  are pivotably mounted to bifurcated heads  45 . The bifurcated heads  45  are operatively attached to rod-shaped extensions  46 . At an end distal from the bifurcated head  45 , the rod-shaped extensions  46  each have an integrally formed ball socket  47 . Each of the ball sockets  47  is operatively connected to a ball head  48 . Each of these ball heads  48  is received at its end facing away from the ball socket  47  by slot guides  49 ,  50  which are conveniently formed in a flange plate  51 . At the top of the flange plate  51  is an integrally formed hollow profile rod  52 , which is operatively connected to a connecting rod  53 . The connecting rod  53  is mounted by a bushing  54 . At its end facing away from the flange plate  51 , the connecting rod  53  is pivotably connected by a bolt  55  to a pivot lever  56 . The pivot lever  56  is rotatably connected to the frame structure  23  of the separating surface  25  by a base bolt  57 . The base bolt  57  is operatively connected to a holding flange  58 . So the pivot lever  56  can perform a pivot movement about the bolt  55  held by the holding flange  58 , the pivot lever  56  is engaged by a piston rod  59  of a lifting cylinder  60 . It is contemplated that the lifting cylinder  60  can be replaced by any displacement apparatus  61  which allows a movement of the pivot lever  56  about the bolt  55  held by the holding flange  58 . 
     As shown in FIG. 4, the piston rod  59  is retracted into the lifting cylinder  60 . In this position the pivot lever  56  which is pivotably connected to the piston rod  59  has displaced the connecting rod  53  so far in the direction of the rear end of the axial separating device  15  that the bolts  48  which traverse the slot guides  49 ,  50  of the flange plate  51  abut against the end of the slot guides  49 ,  50 . Here the bolts  48  are in their lowest position in the vertical direction within the slot guides  49 ,  50 . In this position, the extensions  46  connecting the coupling members  38  to the slot guides  49 ,  50  also occupy their lowest position vertically. As shown in FIG. 3 this leads to the coupling members  38  being held in a position in which the guide bolts  39  associated with them abut against the bottom end of their slot guides  42 . Each coupling member  38  is operatively connected by pivot shaft  37  to the respective closure flap  33 . In this manner each pivot shaft  37  passes through an oblong hole  62  formed in the coupling members  38 . This allows the pivot shafts  37  which pass through the coupling members  38  to be able to compensate for changes of length occurring during pivoting of the coupling members  38 . When coupling member  38  is in the FIG. 3 position, the closure flaps  33  connected by pivot shaft  37  to the coupling member  38  have pivoted in the direction of the separating surface  25 , and are in their closed position indicated at  63 . In closed position, crop  65  is precluded from passing through the through-openings  24  and from being received by subsequent working components, such as a cleaning device  66  known in the art and therefore not described in more detail. can be effectively displaced axially of the axial separating rotor  18 . With the closure flaps  33  in closed position, a separating zone  67  (see FIG. 4) Depending on the number of segments having closure flaps  33 , the length of the closable separating surface  25  can be selected. 
     Referring again to FIG. 4, the lifting cylinder  60  can be selectively pressurized to extend the piston rod  59  and displace connecting rod  53  toward the front end of the axial separating device  15 . Consequently the slot guides  49 ,  50  are also displaced in this direction. In the process, bolt  48  travels first through a region  68  ascending in a vertical direction and the closure flaps  33  pivot from the closed position to an open position as indicated at  70  in FIG.  2 . In the open position the crop  65  passing through the separating surface  25  moves to the subsequent working components. 
     Note that while the closure flaps  33  of the rear segment  28  perform the pivot movement described, the closure flaps  33  of the segment  29  in front remain closed. This is because the front slot guide  49  is differently shaped. If the piston rod  59  is now further extended, the bolt  48  associated with front slot guide  49  passes into a vertically ascending region  68 . In this way the closure flaps  33  of the segment  29  in front are now also pivoted from closed to open position. 
     If the pressurization of the lifting cylinder  60  is now varied in such a way that the piston rod  59  is retracted into the lifting cylinder  60 , the closure flaps  33  of the segments  28 ,  29  pivot in the reverse order. In this way, first the closure flaps  33  of the segment in front  29  in the direction of travel FR pivot from the open position  70  to the closed position  63 , and only when this pivot movement is over do the closure flaps  33  of the segment  28  also move from the open position  70  to the closed position  63 . 
     It is contemplated that the length of closure flaps  33  can be varied in the axial direction  34  of the axial separating device  15 , wherein then the lengths of the individual regions  68 ,  69  of the slot guides  49 ,  50  must be adapted to the new geometrical conditions. Also, the coupling members  38  centrally associated with the segments  28 ,  29  can be arranged at any point in the region of the segments  28 ,  29  in order to force the movement defined by the shape of the slot guides  49 ,  50  on the closure flaps  33 . 
     The example of the axial separating device  15  mounted behind a multi-cylinder threshing mechanism  7  can also be applied to so-called axial threshing and separating rotors  71 , which is shown in FIG.  5 . Such axial threshing and separating rotors  71  are usually divided into a threshing zone  72  and a separating zone  73 , wherein the structure and function of the separating zone  73  essentially correspond to the structure and function of the separating zone  32  already described for the axial separating device  15 , so that the invention is easily applied to the axial threshing and separating rotors  71 . 
     Referring now to FIG. 6, the slot guides  49 ,  50  previously described and which trigger the pivot movement of the closure flaps  33  can be designed as slot guides  75  rotating about a shaft  74  pointing in the axial direction  34  of the axial separating rotor or rotors  18 , wherein the bolt  48  passing through these slot guides  75  in turn transmits, by means of a coupling mechanism  76 , movement defined by the slot guides  75  to the coupling members  38  of the closure flaps  33 . Such a design requires less space, as means for converting a linear movement to a rotational movement can be eliminated. 
     Separate displacement apparatus  61  may be used to move the closure flaps  33  of the segment  28 ,  29  of the separating surface  25 . The actuation of the closure flaps  33  are coordinated with each other in such a way that the closure flaps  33  pivot in a manner according to the invention so that displacement of the earliest separating zone  67  in the axial direction  34  of the axial separating device or devices  15  is possible. 
     In order that the crop  65  passing through the separating surface  25  is not hindered by the closure flaps  33  located in the open position  70 , the closure flaps  33  are shaped in such a way that adjacent closure flaps  33  in the open position  70  span between them creating a throughput zone  77 , which opens in a radial direction as a funnel shape pointing away from the separating surface  25 . 
     In a further advantageous embodiment, at least one sensor unit  79  is placed in a crop stream  78  for sensing the separation of admixtures at the separating surface  25  and for sending the sensed measurement signal or signals  80  to a control unit  81 . In the control unit  81 , depending on the input signal  80  an output signal  82  is generated, which leads to automatic displacement of the earliest separating zone  67  of the separating surface  25 . At its simplest, the output signal  82  can regulate pressurization of the displacement means  61  designed as a lifting cylinder  60 , so that the closure flaps  33  automatically open or close in the manner according to the invention. The closing and opening of the closure flaps  33  are regulated so that with an increasing proportion of admixtures in the separated crop stream  78 , a larger number of the closure flaps  33  is closed. Conversely, with a decreasing proportion of admixtures in the separated crop stream  78 , a large number of closure flaps  33  is opened. 
     The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.