Crop threshing or separating – Threshing – Axial flow through threshing section
Patent
1989-04-10
1991-02-19
Bui, Thuy M.
Crop threshing or separating
Threshing
Axial flow through threshing section
460 67, A01F 1220
Patent
active
049939912
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates generally to farm machinery industry and more specifically to threshing units or mechanisms made use of in axial grain combine harvesters.
The present invention can find most utillity when applied for harvesting such grain crops as wheat, rye, and others, as well as cereals and seeds of legumes and grasses.
BACKGROUND OF THE INVENTION
The cylinder of a known threshing unit of an axial grain combine harvester is arranged longitudinally and performs threshing of the feed material and its translation motion over the concave surface along a helical pathway. The threshing action is effected due to combined impact and rubbing effects produced by the cylinder working members and the concave bars on the crop material being threshed.
Lighter operating duties of the thresher unit featuring the longitudinal cylinder arrangement and substitution of the rubbing action for the impact one make it possible to considerably reduce the degree of grain damage which of grain and seeds and prolonging the storage period of bread grain.
However, the threshing unit of an axial combine harvester, with longitudinally arranged cylinder, apart from the aforesaid advantages, suffer from such a characteristic disadvantage as a one-sided displacement, with respect to the harvester longitudinal axis, of the crop material that has been threshed and passed through the concave, with the result that the cleaning mechanism is charged but nonuniformly uniformly as for width. This in turn lead to grain losses in the course of cleaning and affects adversely the total throughput capacity of the combine harvester. The aforesaid disadvantage stems from the fact that the material being threshed, while running through a helical pathway over the threshing zone, is subjected to repeated effect of the cylinder working members and of the concave bars, the degree of this effect being variable and depending upon the amount of the cylinder-to-concave (or threshing) clearance. Intensity of passing the crop material through the free cross-sectional area of the concave is also variable. It is due to the amount of threshing clearance diminishing towards the exit end of the machine that the traverse speed of the material being threshed over the concave is increased. Thus, the layer of the crop material being handled is spread under the effect of centrifugal forces, which contributes to separation of the material through the concave. As a result of a relative movement of the compacting layers of the crop material in a narrowing threshing clearance and of its active interaction with the concave bars, the threshing and separation process at the concave outlet is intensified. Besides, the crop material separated through the concave by virtue of centrifugal forces, is subjected to the effect of the two differently directed forces, that is, the gravitational force and a force tangential to the traversing pathway of the material being threshed along a circle arc. Non uniformly spread crop material separated through the concave results in an inadequate loading of the cleaning mechanism riddle, which impairs the operation of this mechanism and reduces the total throughput capacity of the combine harvester. Apart from all the aforesaid, when the material being threshed is moving through the threshing clearance, the material is in a compacted state throughout the concave length, which impedes separation of the threshed crop material through the concave and affects the threshing capability of the cylinder working members.
Known in the art is an axial grain combine harvester (cf. U.S. Pat. No. 3,982,549, Cl.AO1F 12/20), wherein the threshing unit comprises a rotary cylinder arranged along the direction of travel of the combine harvester and accommodated in a stationary cylindrical casing whose top portion is provided with helical guide ribs located on the casing internal surface, while the bottom portion of the casing situated in the threshing zone is provided with a change concave.
A disadvantage inherent in the aforedescribe
REFERENCES:
patent: 3982549 (1976-09-01), De Pauw et al.
patent: 4177820 (1979-12-01), Rowland-Hill
patent: 4607480 (1986-08-01), Yarmashev et al.
Tkachev Valentin N.
Yarmashev Jury N.
Zapandi Vladimir A.
Zhurkin Vladimir K.
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