Rotary combine having a frusto-conical rotor housing

A rotary crop processing unit for a combine is shown having a generally cylindrical rotor within a frusto-conical housing. The rotor is arranged in the housing with a generally constant gap between the rotor and the bottom of the housing along the housing length and with an increasing gap between the rotor and the top of the housing in the crop flow direction.

FIELD OF THE INVENTION

The present invention is directed to an agricultural combine rotary crop-processing unit having a rotor disposed within a rotor housing and in particular to such a combine in which the rotor housing is frusto-conical while the rotor is generally cylindrical. The housing is arranged relative to the rotor such that the gap between the rotor and the bottom of the housing is generally constant along the length of the housing while the gap between the top of the rotor and the top of the housing gradually increases in the crop flow direction.

BACKGROUND OF THE INVENTION

Rotary combines having a rotary crop-processing unit are well known. 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. In both of these patents, 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.

In a co-pending patent application, also commonly assigned, Ser. No. 378,773, filed Aug. 20, 1999, the rotor and the housing are both generally cylindrical and are arranged such that their axes are nearly concentric at the inlet and diverge in the crop flow direction with the housing axis diverging upward from the rotor axis in the to produce a gradual increase in the gap between the rotor and the top of the housing in the crop flow direction.

SUMMARY OF THE INVENTION

The present invention provides yet another structure for a crop-processing unit to provide an increasing gap between the top of the rotor and the housing in the crop flow direction. The housing of the present invention is frusto-conical in shape when viewed in a vertical section along the housing axis with the housing arranged relative to the rotor such that the top of the housing diverges from the rotor axis in the crop flow direction. This results in the gap between the rotor and the top of the housing gradually increasing in the crop flow direction. The increasing gap between the rotor and the housing enables the crop mat to expand as it passes through the crop-processing unit which aids in separation of the grain from the straw.

The housing radial section can be either circular or oval. With a circular radial section, the housing can also be mounted in the supporting structure of the combine to rotate about the housing axis as well as having the rotor rotate about the rotor axis.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows an agricultural combine10comprising a supporting structure12having ground engaging means14shown in the form of tires. Alternatively, tracks can be used in place of the tires. A harvesting platform16is used for harvesting crop and directing it to a feederhouse18. The harvested crop is directed by the feederhouse18to a beater20. The beater20directs the crop upwardly to a rotary crop-processing unit24. The rotary crop-processing unit is located between the side sheets of the combine that form part of the supporting structure12. The rotary crop-processing unit24comprises a rotor housing26and a rotor28located in the housing26. The harvested crop enters the housing through an inlet22at the inlet end30of the housing26and travels through an annular space27between the rotor and the housing. The rotor28is provided with an inlet feed portion32, a threshing portion33, and a separating portion34. The rotor housing has a corresponding inlet section36, a threshing section38and separating section40.

Both the threshing portion33and the separating portion34of the rotor are provided with crop engaging members42and44, respectively, shown in FIG.2. The threshing section38of the housing is provided with a concave46while the separating section40of the housing is provided with a grate48. Grain and chaff released from the crop mat falls through the concave46and the grate48. The concave and the grate prevent the passage of crop material larger than grain or chaff from entering the combine cleaning system50below the rotary crop-processing unit.

As illustrated inFIG. 1, grain and chaff falling through the concave and grate is directed to the cleaning system50that removes the chaff from the grain. The clean grain is then directed by an elevator (not shown) to a clean grain tank52where it can be directed to a truck or grain cart by an unloading auger54. Straw that reaches the outlet end55of the housing is expelled through an outlet56to a beater58. The beater58propels the straw out the rear of the combine. The crop material moves through the rotary crop-processing unit in a crop flow direction from the inlet end30to the outlet end55of the housing. The operation of the combine is controlled from the operator's cab60.

The rotor28defines a rotor axis RA about which the rotor is rotated by a rotor drive90. The rotor axis RA is a straight line passing through the center of all three portions of the rotor. The rotor is generally cylindrical, however, as shown inFIG. 2, the diameter of the rotor is not constant along the entire length of the rotor.

The housing26defines a housing axis HA. The housing axis is a straight line passing through all three sections of the housing. The rotor and the housing are arranged relative to one another such that as viewed in a vertical section along the axes of the rotor and housing, the bottom of the rotor and the bottom92of the housing are nearly parallel to one another. As a result of the conical shape of the housing, the top94of the housing diverges from the generally cylindrical rotor in the crop flow direction. The dimension D between the rotor and the top of the housing gradually increases through each section of the housing in the crop flow direction. Since the different portions of the rotor have different diameters, the dimension D will change abruptly at the beginning of a portion of the rotor where the diameter changes. If desired, the rotor diameter can remain constant through the entire length of the rotor, in which case the dimension D would gradually increase along the entire length of the rotor.

With reference toFIG. 3, one embodiment of the invention is shown where the housing26has a radial section that is circular. At any given radial section, the gap between the rotor and the housing will gradually increase around the circumference of the rotor from the bottom of the rotor to the top. An alternative embodiment is shown inFIG. 4where the housing is oval shaped in the radial cross-section. The oval shaped housing enables the gap between the rotor and the housing remain constant over the bottom half of the rotor circumference.

Another embodiment of the invention is shown in FIG.5. There the housing is cylindrical through the inlet section36. Only at the beginning of the threshing section38does the housing become a frusto-conical. The housing can be arranged with a cylindrical infeed section and frusto-conical threshing and separating sections as shown inFIG. 5or both the infeed and threshing sections can be cylindrical while the separating section is frusto-conical. Alternatively, the housing can transition from cylindrical to conical at any location along the housing length, not just at a transition between sections.

A further alternative of invention is shown in FIG.6. There a housing drive96is provided for turning the housing26about the housing axis HA as well as a drive98for rotating the rotor28. Unlike the crop-processing units shown in the '563 and the '170 patents mentioned above, the frusto-conical housing can be rotated relative to the combine supporting structure as well as the rotor. This design, as shown in U.S. Pat. No. 4,274,426, provides greater flexibility in setting the operating speed of the crop-processing unit.

The frusto-conical housing together with a cylindrical rotor provide a crop processing unit in which the gap between the rotor and the top of the housing can increase in the crop flow direction. The invention should not be limited to the above-described embodiment, but should be limited solely by the claims that follow.