Abstract:
An axial separator of an agricultural combine comprises a rotor housed in a housing. The housing includes a lower separating grate and a top cover plate with spiral-shaped guide vanes, which are aligned to feed harvested crop on a helical path. A section of one of the guide vanes forms an acute angle with the housing as it extends outwardly therefrom.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is directed to an axial separator wherein the upper cover plate is provided with a spiral-shaped guide vane, to guide harvested crop on a helical path.  
         BACKGROUND OF THE INVENTION  
         [0002]    A combine with an axial separator is described in U.S. Pat. No. 3,828,794 A. The axial separator includes a rotor which has crop processing elements and which extends in the direction of travel of the combine and is arranged inside a housing. On the plate of the housing there are grates, through which threshed grains fall and are fed to a cleaning device. Spiral-shaped guide vanes are attached to the top side of the housing, which are used to lead the crop gradually backwards.  
           [0003]    The guide vanes extend in spiral form radially relative to the axis of the rotor. The optimum pitch of the guide vanes, i.e., the degree by which their downstream end is shifted backwards against the direction of travel relative to the upstream end (or their angle to the rotor axis), can depend on the type of crop being processed. For crops with relatively small grains, such as wheat, it is important to maintain low power requirements for the axial separator, which means a relatively large pitch of the guide vanes, because the crop then leaves the axial separator faster, so that only a smaller amount of crop has to be moved in the axial separator. On the other hand, one goal for crops with rather large grains, such as peas and corn, is to keep the so-called dribble losses low. These losses are generated when the grains impact the guide vanes and are deflected in the direction towards the rear side of the axial separating device, where they leave the combine and are lost. To maintain low dribble losses, it is important that the guide vanes have a relatively small pitch. It is certainly possible to exchange the cover plates filled with guide vanes in order to adapt to the type of crop to be harvested, but this is very expensive.  
         SUMMARY OF THE INVENTION  
         [0004]    It is an object of the present invention to provide improved guide vanes for an axial separator.  
           [0005]    It is proposed to orient the surface of one section of one guide vane (or several or all guide vanes of an axial separating device) at an acute angle to the radial direction of the rotor. If grains impact the surface of the guide vane according to the invention, they are not deflected exactly backwards, where they can be lost from the harvesting process, but instead they are deflected downwards or upwards, so that they are further guided together with the crop and led through the separating grate to the cleaning device.  
           [0006]    In this way, particularly for crops with rather large grains, the loss of grains is reduced. It is possible to also use guide vanes with a relatively large slope for such crops, so that when there is a change in the type of harvested crop, a replacement of the cover plates for changing the slope of the guide vanes is not necessary. The guide vanes according to the invention can be used for axial separating devices, which feature a threshing section and a separating section, and also for axial separating devices, which are arranged behind a conventional threshing cylinder.  
           [0007]    With reference to the direction of the surface of the guide vane not extending radial to the axis of the rotor, various possibilities are conceivable with the scope of the design according to the invention. In one embodiment, the guide vane features one section extending forward or the guide vane extends forwards across its entire height. Grains meeting this section from behind are thus deflected downwards. On the other hand, the guide vanes can also feature a section extending backwards (or extending backwards as a whole), by which the grains are deflected upwards. They then meet the housing of the axial separating device and are again deflected downwards from there so that they are guided into the crop flow. One advantage of guide vanes angled backwards is that no crop can collect at their front side. It is also conceivable to use guide vanes with triangular cross sections, which are manufactured as hollow profiles or as solid bodies. These guide vanes can feature a front surface extending approximately radially and a rear surface extending diagonally backwards at an acute angle to the housing. One angle of the triangle is thus attached to the cover plate. Such guide vanes have the advantage that they actively guide the crop on their front side and generate no undesired dribble losses at their rear side. However, it is also conceivable to arrange the front wall radially to the rotor axis and to incline the rear wall downwards. This produces a triangle standing on its apex.  
           [0008]    The sections of the guide vanes angled forwards or backwards can also be combined with sections extending radially to the axis of the rotor.  
           [0009]    In another embodiment, the guide vane has a sinusoidal cross section. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a side schematic view of a combine.  
         [0011]    [0011]FIG. 2 is a perspective view of the axial separator.  
         [0012]    [0012]FIG. 3 is a cross sectional view of a first embodiment of the guide vanes of the axial separator.  
         [0013]    [0013]FIG. 4 is a cross sectional view of a second embodiment of the guide vanes of the axial separator.  
         [0014]    [0014]FIG. 5 is a cross sectional view of a third embodiment of the guide vanes of the axial separator.  
         [0015]    [0015]FIG. 6 is a cross sectional view of a fourth embodiment of the guide vanes of the axial separator.  
         [0016]    [0016]FIG. 7 is a cross sectional view of a fifth embodiment of the guide vanes of the axial separator. 
     
    
     DETAILED DESCRIPTION  
       [0017]    [0017]FIG. 1 shows an agricultural combine  10  having a support frame  12  that is supported on and propelled by wheels  14 . The wheels  14  are driven by a drive assembly, not shown, powered by internal combustion engine  48 . A harvesting assembly  16  is mounted on a feeder house  18  that extends forwardly from the combine  10 . The harvesting assembly  16  harvests agricultural crops and directs them to the feeder house  18  which conveys the harvested crop material upwardly and rearwardly into the combine  10 . The feeder house  18  directs the harvested crop material to a threshing assembly that comprises a transverse threshing cylinder  20  and an associated concave  21 . The threshed crops are then fed to a scraper roller  23  and a beater  22  which directs the threshed crop material into an axial separator  24 . However, it is also conceivable to exclude the transverse threshing cylinder  20  and concave  21  and to use an axial threshing assembly that is integral with and extends forwardly from the axial separator  24 . There can be a single axial separator or two (or more) axial separators.  
         [0018]    Grain and chaff, which are separated during the threshing process, fall onto at least one auger  30 , which feeds these materials to a grain pan  33 . In contrast, grain and chaff, which exit the axial separator  24 , fall onto a shaker plate  32 , and then continue to the grain pan  33 . The grain pan  33  advances the grain and chaff to a sieve  34 , which is associated with a cleaning fan  36  that blows chaff out the rear of the combine  10  and allows clean grain to fall to grain auger  38 . The grain auger  38  collects the grain and directs it to an elevator, not shown, which elevates the clean grain to grain tank  40 . A returns auger  42  directs unthreshed heads through another elevator (not shown) back to the threshing assembly. Finally, the cleaned grain is unloaded from the grain tank  40  by an unloading assembly comprising cross augers  44  and unloading conveyor  46 .  
         [0019]    All of the various systems mentioned above are driven by means of an internal combustion engine  48 , which is operated by an operator from cab  50 . The various devices for threshing, conveying, cleaning, and separating are located within the support frame  12 .  
         [0020]    The configuration of the axial separator  24  is shown best in FIG. 2. The feeding zone for both units of the axial separator extends from a front cross plate  54  to cross plate  56  and is provided with a bottom plate  58 . From the bottom plate  58 , spiral-shaped guide vanes  60  extend upwards, which are illustrated with broken lines and which move the threshed crop backwards into a separating zone. In the feeding zone, the rotor is equipped with rigidly attached prongs  62 , which are shorter than the prongs  78  located in the separating zone of the axial separator  24 . A cover  64  in the feeding zone has guide vanes  66  directed downwards, which move the threshed crop backwards within the feeding zone.  
         [0021]    The separating zone extends from cross plate  56  to cross plate  70 . The grate region of each unit of the axial separator  24  is provided in the separating zone with a separating grate, which is assembled from finger grates  72 . Grain and chaff, which are separated in the separating zone from the crop, fall through the finger grates  72  onto the shaker plate  32 . Upper cover plates  74  for the separating zone are equipped with spiral-shaped sliding runners or guide vanes  76  extending inwards for moving the material backwards. Because the grate region is not filled with spiral-shaped guide vanes  76  in the separating zone, the prongs  78  rigidly attached in the separating zone to rotor  100  are longer than the prongs  62 .  
         [0022]    An output zone extends from the fourth cross plate  70  up to a rear cross plate  80 . The output zone is open at the bottom. The cover over the output zone is an extension of the top cover plate  74  and is also equipped with spiral-shaped guide vanes. From the axial separator  24 , threshed crop residue (straw) is discharged downwards through the open bottom. Due to the effect of the force of gravity, the crop residue falls onto a straw guiding sheet  91  and exits the combine  10  downwards through an opening in the plate of the output hood  92  and is laid on the field as a swath.  
         [0023]    [0023]FIG. 3 shows a vertical cross section taken along the longitudinal axis of the axial separator  24  through a first embodiment of the guide vanes  76  according to the invention. The guide vanes  76 , which cannot be seen in FIG. 2 due to the significantly smaller representation, are not arranged radially to the axis of the rotor  100 , but at an angle to this axis. The guide vanes according to FIG. 3 feature a top section  76   a , which extends from the cover plate  74  at an angle of approximately 45° downwards and forwards against the direction of the crop flow. The top section  76   a  transitions into a lower section  76   b , which extends downwards approximately vertical.  
         [0024]    The second embodiment of the guide vanes  76  according to FIG. 4 features only a single section, which extends downwards from the cover plate  74  at an angle of approximately 45° diagonally and forwards against the direction of the crop flow.  
         [0025]    The third embodiment of the guide vanes  76  according to FIG. 5 features only a single section, which extends from the cover plate  74  at an angle of approximately 45° diagonally downwards and backwards in the direction of the crop flow.  
         [0026]    [0026]FIG. 6 represents a fourth embodiment of the guide vanes  76 . The guide vanes  76  have a sinusoid shape and extend downwards from the cover plate  74 .  
         [0027]    In FIG. 7, a cross section through a fifth embodiment of the guide vanes  76  is shown. The guide vane  76  is a triangular hollow profile. A front wall of the hollow profile extends downwards from the cover plate  74  approximately radially to the axis of the rotor  100 . A back wall of the hollow profile extends approximately like the guide vane  76  of FIG. 5. The two walls are connected to each other by a third, lower wall, which extends diagonally backwards and upwards from the lower edge of the front wall up to the lower edge of the back wall.  
         [0028]    The guide vanes  76  illustrated in FIGS.  3 - 7  extend in the form of a spiral to the top side of the cover plates  74 , as illustrated in FIG. 2. Their cross section is preferably constant across the length of the guide vanes, although it would also be possible for the cross section to vary over the length. Thus, the guide vanes  76  could first extend radially to the axis of the rotor  100  at the left and right ends, i.e., starting from the separating grate, and transition continuously into a cross section not oriented radially, as illustrated in FIGS.  3 - 6 . The guide vanes  76  can also appear in the feeding zone instead of the guide vanes  60  oriented radially to the axis of the rotor  100 . It is also conceivable to distribute guide vanes  76  of different cross sections across the length of the rotor  100  in a combine  10 . Thus, one or more types of guide vanes  76  according to FIGS.  3 - 7  and/or mixed with radially oriented guide vanes can be distributed across the length of the rotors  100 .  
         [0029]    Having described the illustrated 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.