Abstract:
A threshing and separating mechanism for a combine includes an elongated rotor mounted for rotation about a rotor axis on the combine within a rotor housing. The rotor has a threshing portion and a separating portion. The housing has a threshing section and a separating section corresponding to the threshing portion and the separating portion. The housing surrounds the rotor and is spaced from the rotor to form an annular space between the rotor and the housing for crop material to flow through in an axial crop flow direction from an inlet end of the housing to an outlet end of the housing. The housing includes a smooth transition section between the threshing section and the separating section of the housing.

Description:
FIELD OF THE INVENTION 
     The invention relates to rotors and housings for axial rotary agricultural combines. 
     BACKGROUND OF THE INVENTION 
     Agricultural combines are large machines that harvest, thresh, separate and clean an agricultural crop. The resulting clean grain is stored in a grain tank located on the combine. The clean grain can then be transported from the grain tank to a truck, grain cart or other receiving bin by an unloading auger. 
     Rotary combines have one or two large rotors for threshing and separating the harvested crop material. In most rotary combines the rotor or rotors are arranged along the longitudinal axis of the machine. These rotors are provided with an infeed section for receiving harvested crop material, a threshing section for threshing the harvested crop material received from the infeed section and a separating section for freeing grain trapped in the threshed crop material received from the threshing section. 
     Rotors have been provided for combines in a variety of configurations to optimize harvesting efficiency for a wide variety of crops and crop conditions. Examples are shown in U.S. Pat. Nos. 5,445,563 and 5,688,170 assigned to the assignee of the present application. These two patents both disclose rotary crop processing units having two or more sections. The relationship between the rotor axis and the housing axis varies from one section to the other. The rotor axis becomes increasingly offset from the housing axis in the crop flow direction from the housing inlet to the housing outlet. This is accomplished by abrupt transitions in the housing structure between sections where the housing shape changes. As the housing shape changes, the housing axis steps upward relative to the rotor axis and the gap between the rotor and the top of the housing increases at each step in the housing. 
     U.S. Pat. No. 7,070,498 describes a combine rotor having both infeed and threshing sections on a common frusto-conical portion of the rotor drum. The rotor in the infeed section is provided with helical infeed elements located on the fore-region of the frusto-conical portion of the drum. Immediately downstream from the infeed section, the threshing section is provided with a number of threshing elements. A portion of the threshing elements are attached to the aft-region of the frusto-conical portion of the drum, with the remaining portion being attached to the rearward cylindrical portion. 
     In such rotary combines, due to the shape and sizing of the housing covers, the rotor housing expands in steps as the material moves rearward. The first step is over the threshing area. The other expansion point is over the separator portion of the rotor. For a rotor design such as disclosed in U.S. Pat. No. 7,070,498, the annular gap defined between the top cover and the rotor tapers to a minimum at the midpoint of the threshing section. The annular gap defined between the rotor and the cover step expands again at the start of the separating section. This abrupt expansion causes excess or wasted power consumption, excess wear and straw damage without increasing threshing capacity. 
     The present inventors have recognized that a need exists for providing a rotor housing for an axial rotary agricultural combine that provides for efficient energy consumption, an increased wear life, and decreased threshing damage to the grain harvested. 
     SUMMARY OF THE INVENTION 
     The invention provides a threshing and separating mechanism for a combine. The mechanism includes an elongated rotor mounted for rotation about a rotor axis on the combine within a rotor housing. The rotor has a threshing portion and a separating portion. The housing has a threshing section and a separating section corresponding to the threshing portion and the separating portion. The housing surrounds the rotor and is spaced from the rotor to form an annular space between the rotor and the housing for crop material to flow through in an axial crop flow direction from an inlet end of the housing to an outlet end of the housing. 
     The housing has a top that is raised above the rotor to define a first distance between the top of the threshing section of the housing and the rotor axis, and a second distance between the top separating section of the housing and the rotor axis. 
     The housing includes a transition section between the threshing section and the separating section of the housing. The transition section is arranged over an outlet portion of the threshing portion of the rotor and an inlet portion of the separating portion of the rotor. The top of the housing is raised above the rotor at an inlet end of the transition section to define a third distance between the rotor axis and the top of the transition section. The top of the housing is raised above the rotor at an outlet end of the transition section to define a fourth distance between the rotor axis and the top of the transition section, the third distance substantially equal to the first distance and the fourth distance substantially equal to the second distance. 
     This configuration provides a smooth, energy-efficient, wear resistant, and crop protecting transition of crop material flow between the threshing section and the separating section of the rotor housing. 
     According to one embodiment, the housing has a top that is raised above the rotor to define a first gap between the top of the threshing section of the housing and the rotor, and a second gap between the top separating section of the housing and the rotor. 
     According to this embodiment the housing includes a transition section between the threshing section and the separating section of the housing. The transition section is arranged over an outlet portion of the threshing portion of the rotor and an inlet portion of the separating portion of the rotor. The top of the housing is raised above the rotor at an inlet end of the transition section to define a third gap between the rotor and the top of the transition section. The top of the housing is raised above the rotor at an outlet end of the transition section to define a fourth gap between the rotor and the top of the transition section, the third gap substantially equal to the first gap and the fourth gap substantially equal to the second gap. 
     This configuration also provides a smooth, energy-efficient, wear resistant, and crop protecting transition of crop material flow between the threshing section and the separating section of the rotor housing. 
     According to another embodiment, the transition section of the housing, when viewed in a vertical section along the housing axis, is frusto-conical and the gap between the rotor and the top of the housing continuously increases in the crop flow direction within the threshing section and within the separating section. 
     Preferably, the rotor comprises a tube, that when viewed in a vertical section along the housing axis, is frusto-conical within the threshing section. 
     The invention also provides an axial flow combine for harvesting, threshing and separating crop material that includes a supporting structure, wheels, tracks or the like extending from the supporting structure for transporting the supporting structure around a field, and a threshing and separating mechanism supported on the supporting structure. 
     The threshing and separating mechanism includes a rotor housing located inside the supporting structure. The rotor housing is provided with a threshing section in which crop material is threshed and a separating section in which threshed grain is separated from threshed crop material. A rotor is located in the rotor housing having a rotor axis, wherein the rotor is provided with crop engaging assemblies for engaging crop material passing through the rotor housing. The threshing section of the rotor housing is arranged so that the threshing axis has a first eccentricity with respect to the rotor axis and the separating section of the rotor housing is arranged so that the separating axis has a second eccentricity with respect to the rotor axis, the first eccentricityl being less than the second eccentricity. A substantially frusto-conical transition section connects the threshing section of the rotor housing to the separating section of the rotor housing. 
     Preferably, the rotor housing is arranged so that the separating axis is located parallel to and above the rotor axis. 
     Preferably, the housing separating section includes a separating grate. 
     The transition section of the housing lowers power consumption and increases throughput of the rotor. The coned transition top cover is at an angle similar to the rotor taper in the threshing section for increased flow with a gradual expansion to the separating section. This gradual expansion also decreases wear on the rotor and rotor housing and decreases crop damage. 
     Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, and from the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic side view of an agricultural combine the present invention; 
         FIG. 2  is a diagrammatic side view of a crop processing unit taken from the combine shown in  FIG. 1 ; 
         FIG. 2A  is a diagrammatic side view of a crop processing unit taken from the combine shown in  FIG. 1  with an alternate rotor; 
         FIG. 2B  is a diagrammatic side view of a crop processing unit taken from the combine shown in  FIG. 1  with a further alternate rotor; 
         FIG. 3  is a perspective view of a cover for a crop processing unit of  FIG. 2 ; 
         FIG. 4  is a side view of the cover shown in  FIG. 3 ; 
         FIG. 5  is a bottom view of the cover shown in  FIG. 3 ; 
         FIG. 6  is a perspective bottom view of the cover shown in  FIG. 3 ; 
         FIG. 7  is a sectional view taken generally along line  7 - 7  of  FIG. 2 ; 
         FIG. 8  is a sectional view taken generally along line  8 - 8  of  FIG. 2 ; and 
         FIG. 9  is a sectional view taken generally along line  9 - 9  of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
       FIG. 1  shows an agricultural combine  10  comprising a supporting structure  12  having ground engaging wheels  14  extending from the supporting structure. The operation of the combine is controlled from operator&#39;s cab  15 . A harvesting platform  16  is used for harvesting a crop and directing it to a feederhouse  18 . The harvested crop is directed by the feederhouse  18  to a beater  20 . The beater directs the crop upwardly through an inlet transition section  22  to the axial crop processing unit  24 . 
     The crop processing unit  24  threshes and separates the harvested crop material. Grain and chaff fall through grates on the bottom of the unit  24  to the cleaning system  26 . The cleaning system  26  removes the chaff and directs the clean grain to a clean grain elevator (not shown). The clean grain elevator deposits the clean grain in grain tank  28 . The clean grain in the tank  28  can be unloaded into a grain cart or truck by unloading auger  30 . Threshed and separated straw is discharged from the axial crop processing unit  24  through outlet  32  to discharge beater  34 . The discharge beater  34  in turn propels the straw out the rear of the combine. 
     As illustrated in  FIG. 2 , the axial crop processing unit  24  comprises a rotor housing  36  and a rotor  37  located inside the housing  36 . The front part of the rotor  37  and the rotor housing  36  define the infeed section  38  of the crop processing unit. Longitudinally downstream from the infeed section  38  are threshing section  39  and separating section  40 . The rotor  37  comprises a drum  100  to which crop processing elements for the infeed section, threshing section, and separating section are affixed. The drum  100  comprises a rearward cylindrical portion  102  and a forwardly extending frusto-conical portion  104 . 
     The rotor  37  shown in  FIG. 2  is similar to the rotor explained in more detail in U.S. Pat. No. 7,070,498, herein incorporated by reference. However, in contrast to the rotor shown in U.S. Pat. No. 7,070,498, the rotor  37  within the threshing section  39  includes a long tapered profile throughout the threshing section  39  without the cylindrical portion within the threshing section as described in U.S. Pat. No. 7,070,498. Alternatively, the rotor could be a rotor having the shape such as shown U.S. Pat. No. 5,688,170. The invention is useful with and encompasses all of these rotors. 
     The rotor  37  in the infeed section  38  is provided with helical infeed elements  42  located on the frusto-conical portion of the drum  100 . The helical infeed elements  42  engage harvested crop material received from the beater  20  and inlet transition section  22 . 
     In the threshing section  39  the rotor  37  is provided with a number of threshing elements  122  for threshing the harvested crop material received from the infeed section  38 . 
     The separating section  40  of the rotor includes outwardly projecting tines  126  similar to the tines disclosed in FIGS. 11 and 12 of U.S. Pat. No. 5,112,279, herein incorporated by reference. 
     The threshing section  39  of the rotor housing is provided with a concave  146  and the separating section  40  is provided with a grate  148 . Grain and chaff released from the crop mat falls through the concave  146  and the grate  148 . The concave and grate prevent the passage of crop material larger than grain or chaff from entering the cleaning system  26 . 
     The rotor is axially arranged in the combine and defines a central rotor axis RA. The rotor axis RA is a straight line passing through the infeed, threshing and separating portions of the rotor. 
     As seen in  FIG. 7 , the infeed section  38  of the rotor housing  36  is provided with a closed cover  162  and a closed bottom  164 . The cover  162  is provided with helical indexing vanes  165 . The cover and bottom are bolted to axial rails  166  and  168 . The forward portion of the closed bottom  164  is provided with an inlet transition section which is similar to one of those disclosed in U.S. Pat. No. 7,070,498 or U.S. Pat. No. 5,344,367, herein incorporated by reference. 
     The closed cover  162  of the infeed section  38  defines an infeed axis IA. The infeed axis IA is parallel to and substantially collinear with the rotor axis RA defined by the rotor. As such, the infeed portion of the rotor is substantially concentrically arranged in the infeed section  38  of the rotor housing as defined by the cover  162 . 
     As seen in  FIG. 8 , the threshing section  39  is provided with a closed threshing cover  172  having helical vanes  174 . The cover is bolted to axial rails  166  and  168 . The concave  146  is pivotally mounted to the frame of the combine below rail  168  at  175 . An adjustment assembly  176  for adjusting concave clearance is mounted to the frame of the combine below rail  166 . The concave  146  is provided with a closed extension  178 . 
     The threshing cover  172  defines a threshing axis TA that is parallel to the rotor axis RA. The threshing axis is located above the rotor axis RA. In addition, the threshing axis is slightly offset to the side of the rotor axis in a downstream direction. As such, the cover of the threshing section is eccentrically arranged relative to the threshing portion of the rotor. 
     The separating section  40  is provided with a separating cover  180  having helical vanes  182 . The cover is bolted to axial rails  166  and  168 . Grate  148  is also bolted to rails  166  and  168 . Grate  148  is similar to the grate disclosed in U.S. Pat. No. 4,875,891. 
     The separating cover  180  defines a separating axis SA that is parallel to the rotor axis RA. The separating axis is located above the rotor axis RA. In addition, the separating axis is offset to the side of the rotor axis in a downstream direction. As such, the cover of the separating section is eccentrically arranged relative to the separating portion of the rotor. 
     According to the preferred embodiment of the present invention, a frusto-conical transition section  200  is provided between the threshing section  39  and the separating section  40 , overlapping each section. 
     The transition section  200  includes a cover  210  having a substantially frusto-conical curvature. The cover  210  includes vanes  214   a ,  214   b . The vane  214   a  has a relatively wide width similar to the vanes  174  of the threshing section  39 . The vane  214   a  is substantially continuous with the last vane  182   a  of the separating section  40 . The vane  214   b  has a relatively wide width section  214   c  similar to the width of the vane  174  of the threshing section  39 , and a relatively thinner width section  214   d  similar to the width of the vane  182  of the separating section  40 . 
     Preferably, for smooth, energy-efficient flow, the cover  210  has a taper angle “G” that is substantially equal to a taper angle “H” of the rotor drum  100  within the threshing section  39  for the rotor shown in  FIG. 2 . 
     Some rotors provided a further, reverse taper portion  220  of the rotor drum  100  at an outlet end of the processing unit  24  having an angle of taper “J.” A deflecting plate  180   a  in the separator cover  180  can be arranged over the reverse taper portion  220  to provide for a smooth, energy-efficient flow of crop material. Preferably the deflecting plate taper angle “K” is preferably substantially equal to the rotor angle “J.” 
     The rotor  37   a  shown in  FIG. 2A  is substantially the same rotor in U.S. Pat. No. 7,070,498. The rotor  37   b  shown in  FIG. 2B  such as shown U.S. Pat. No. 5,688,170. As can be seen in these diagrammatic side views of  FIGS. 2 ,  2 A and  2 B, the transition section  200  of the housing  36  allows for a smooth flow transition and a gradually increasing radial distance “D” between the top of the housing cover  210  and the rotor axis from the inlet of the transition section  200  to the outlet of the transition section  200 . Also, for  FIGS. 2A and 2B  there is a gap “P”, taken between the rotor and the top of the housing cover  210  from the inlet to the outlet of the transition section  200  that gradually increases within the threshing section and within the separating section. 
     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred.