Rotor cage to transition cone interface for agricultural harvester

A threshing system of an agricultural harvester includes a rotor cage surrounding a rotor, a threshing space defined between the rotor cage and the rotor, and a transition cone defining an infeed to the rotor cage and the threshing system. A mating interface between the rotor cage and the transition cone is curved in three different dimensions of a Cartesian coordinate system for maximizing the threshing space. As viewed from above the mating interface of the threshing system, a convex portion of the rotor cage is mounted to a concave portion of the transition cone.

FIELD OF THE INVENTION

The present invention relates to an interface between a rotor cage and a transition cone for a combine harvester.

BACKGROUND OF THE INVENTION

As is described in U.S. Patent Application No. 2017/0105350 to CNH America LLC, which is incorporated by reference in its entirety and for all purposes, a rotary threshing or separating system of an agricultural combine harvester includes one or more rotors which can extend axially (front to rear) or transversely (side to side) within the body of the combine, and which are partially or fully surrounded by a perforated concave. The crop material is threshed and separated by the rotation of the rotor within the concave. Coarser non-grain crop material such as stalks and leaves are transported to the rear of the combine and discharged back to the field. The separated grain, together with some finer non-grain crop material such as chaff, dust, straw, and other crop residue are discharged through the concaves and fall onto a grain pan where they are transported to the cleaning system. Alternatively, the grain and finer non-grain crop material may also fall directly onto the cleaning system itself.

In combines having a rotor operating within a concave formed as a rotor cage, it is known to provide a transition cone between a feeder housing and the rotor cage. The transition cone narrows along its length, from the upstream end to the downstream end of the cone. An auger flight operated by the rotor transports the cut crop material through the transition cone, from the feeder housing and to the rotor cage. It is known to provide helical vanes on the inside surface of the transition cone, to facilitate efficient transport of crop material through the transition cone. During use, the crop material tends to follow along the transition cone vane and is somewhat compressed against the inside surface of the narrowing cone.

Referring now to the drawings, and more particularly toFIG. 1, there is shown a conventional threshing and separating system24. The threshing and separating system24generally includes a rotor40at least partially enclosed by and rotatable within a corresponding perforated semi-cylindrical rotor cage42. The cut crops are threshed and separated by the rotation of rotor40within rotor cage42, and larger elements, such as stalks, leaves and the like are discharged from the rear of combine10. Smaller elements of crop material including grain and non-grain crop material, including particles lighter than grain, such as chaff, dust and straw, are discharged through perforations of rotor cage42. Rotor40is shown in a representative sense in that rotor40may be more than one rotor40and may be oriented generally in line with the direction of travel of combine10. Grain that has been separated by threshing and separating assembly24falls onto a grain pan and is conveyed toward cleaning system.

Rotor40includes a downstream portion having threshing elements72, and an upstream portion defining an inlet auger74having an auger flight or flights76. The cylindrically shaped rotor cage42includes a concave or concaves78operating together with threshing elements72of rotor40to separate grain from crop material. A transition cone80is connected to rotor cage42and defines an infeed to the threshing zone of rotor40and rotor cage42. Transition cone80has a hollow conical shape including an inner cone surface82having a larger diameter at the upstream end84thereof and tapering to a smaller diameter at the downstream edge86thereof, thereby defining a decreasing inner circumference about the inner surface from upstream end84to downstream end86. At least one and typically a plurality of helical or spiral vanes88is provided on the inner surface of transition cone80. Inlet auger74operates within transition cone80, and crop material is transferred through transition cone80under the force applied by rotating auger flight76, the directional guidance provided by vanes88and the influence supplied by the tapering conical shape of transition cone80.

In operation, the inlet of the rotor cage42experiences high wear due to the tight radial clearance between the rotor cage42and the rotor40. What is desired in the art is greater clearance between the rotor40and the rotor cage42to allow for expansion of the crop material in that region, which would permit the grain to migrate to the outside of the crop material for better separation. Simply enlarging the rotor cage is not necessarily possible in all harvesters due to vertical clearance limitations within the harvester.

SUMMARY OF THE INVENTION

The present invention provides a modified rotor cage having greater clearance between the rotor and the rotor cage, and a modified transition cone for mounting to the modified rotor cage.

More particularly, according to one aspect of the invention, a threshing system of an agricultural harvester comprises a rotor cage surrounding a rotor, a threshing space defined between the rotor cage and the rotor, and a transition cone defining an infeed to said rotor cage and said threshing system, the transition cone mounted to said rotor cage at a location upstream of the rotor cage, as viewed in a direction of crop flow through the threshing system, wherein a mating interface between the rotor cage and the transition cone is curved in three different dimensions of a Cartesian coordinate system for maximizing the threshing space.

According to another aspect of the invention, as viewed from above the mating interface of the threshing system, a convex portion of the rotor cage is mounted to a concave portion of the transition cone.

DETAILED DESCRIPTION OF THE INVENTION

The terms “grain”, “straw” and “tailings” are used principally throughout this specification for convenience but it is to be understood that these terms are not intended to be limiting. “Grain” refers to that part of the crop material which is threshed and separated from the discardable part of the crop material, which is referred to as non-grain crop material, MOG or straw. Incompletely threshed crop material is referred to as “tailings”. Also the terms “forward”, “rearward”, “left” and “right”, when used in connection with the agricultural harvester and/or components thereof are usually determined with reference to the direction of forward operative travel of the harvester, but again, they should not be construed as limiting. The terms “longitudinal” and “transverse” are determined with reference to the fore-and-aft direction of the agricultural harvester and are equally not to be construed as limiting.

FIGS. 2-4depict a threshing and separating system200according to the present invention. System200is similar to system24ofFIG. 1, and the primary differences between those systems will be described hereinafter.

System200includes a rotor240(shown schematically) at least partially enclosed by and rotatable within a corresponding perforated semi-cylindrical rotor cage242. Transition cone280(hereinafter “cone”) is connected to rotor cage242(hereinafter “cage”) at a mating interface206/218. Cone280defines an infeed to the threshing zone of the rotor240and cage242.

FIGS. 6-8depict cage242. Cage242has a semi-cylindrical body including a curved portion202having a pre-defined constant radius ‘R,’ and straight portions204extending downward from each end of curved portion202. Each straight portion204has a defined length ‘L.’ The lengths of straight portions204are equal according to this embodiment. The lengths ‘L’ and radius ‘R’ can be varied to meet the space requirements for different systems200. A flange205extends perpendicularly from the end of each straight portion204. Each flange205extends outwardly in a direction away from longitudinal axis ‘A’ of system200. Flanges205are provided for bolting to other components of system200. Cage242may have a constant wall thickness ‘t.’

Upstream edge206of cage242, which mates with cone280by welds or fasteners (for example), is three dimensional and extends in three different directions. More particularly, upstream edge206is curved as viewed in a Y-Z plane (seeFIG. 6) of an X-Y-Z Cartesian coordinate system. Upstream edge206is convexly curved as viewed in an X-Z plane (seeFIG. 8) such that the top center of the upstream edge206at point ‘V’ protrudes outwardly in an upstream direction beyond straight portions204and flanges205. Upstream edge206is also curved as viewed in the X-Y plane (seeFIG. 7) along radius ‘R.’ Radius R1of upstream edge206in the X-Z plane is tailored to compliment the radius of edge218of cone280.

As best shown inFIG. 5, transition cone280is connected to upstream edge206of cage242. Cone280defines an infeed to the threshing zone between rotor240and cage242. Transition cone280has a curved panel210. A hood may be bolted to a flange213at the upstream end214of panel210. Flange213, which is provided at (or mounted to) an upstream edge214of panel210, protrudes outwardly in a direction away from axis A, and is curved in the X-Y plane, but not the X-Z plane. Flange213could be replaced by an edge, if so desired.

Referring now to panel210of cone280, panel210is either frusto-conical or semi-frusto-conical and comprises one or more sheets of material. In the axial direction, panel210extends between an upstream edge214, which is adjacent the flange213, and a downstream edge218, which is mounted to the cage242.

The downstream edge218of the cone280comprises a top edge218A and bottom edge218B. The top edge218A of the cone280is curved to compliment and mate with upstream edge206of cage242. Edge218A appears concave as viewed from above. More particularly, edge218A is also curved as viewed in the X-Y plane and has radius ‘R’ like cage242. Downstream edge218A is also curved as viewed in an X-Z plane and has radius ‘R1’ (like cage242) such that the top center ‘P’ of the downstream edge218A protrudes inwardly in an upstream direction with respect to the bottom edge218B. Edge218B, like flange213, comprises a flange and is curved in the X-Y plane, but not the X-Z plane.

The top end of panel210slopes downward in the downstream direction from the top center upstream end point ‘T’ of panel210to the top center downstream end point ‘P.’ Stated differently, the radial distance between the axis A and the top center upstream end point ‘T’ of panel210is greater than the radial distance between the axis A and the top center downstream end point ‘P.’ The top end of panel210, which decreases in diameter in the downstream direction, acts as a funnel in the downstream direction to channel the crop mat to the threshing zone between rotor240and cage242.

The top center of panel210slopes downwardly in the downstream direction (i.e., toward axis A) to only a limited extent so as to create a funnel so that the crop mat passes from the hood (not shown) to the threshing zone, without sacrificing (i.e., without minimizing) the vertical clearance between rotor240and rotor cage242that constitutes the threshing zone. If the top center downstream end point ‘P’ at the interface between cone280and cage242were positioned any lower (i.e., closer to axis A), then sufficient vertical clearance between rotor240and cage242might not exist. It was discovered that curving the edge218A of cone208in the X-Y plane as well as the X-Z plane achieves both goals of (i) funneling the crop mat to the threshing zone, and (ii) maximizing the size of the threshing zone.

Cone280and cage242may be composed of steel sheet metal material, for example, or any other material known to those skilled in the art.

By virtue of the geometry of cone280and cage242it is possible to both funnel crop material to the threshing zone and maintain a large radial clearance between rotor240and cage242. The raised rotor cage provides more relief to the crop mat between the rotor and the rotor cage, which allows the crop mat to expand and grain to migrate to the outside of the crop mat for improved separation.