Abstract: A rotary cleaning mechanism for combine harvesters is disclosed wherein an impeller is positioned within the axial opening formed through the rotatable cleaning cylinder by the circumferentially spaced cleaning shoes. The impeller has an axial length substantially equal to the length of the sieves mounted within the cleaning shoes and is operable to deflect any grain falling radially inwardly from the sieves back outwardly into the cleaning shoes so that the centrifugal force generated by the rotation of the cleaning cylinder is operable to help clean the grain. The impeller has a four-blade construction and is rotatable with a drive shaft passing through the axial opening in the cleaning cylinder to be driven at a speed greater than the cleaning cylinder.

Abstract: A method for cleaning threshed grain in a combine harvester is disclosed wherein the threshed grain is conveyed into a cleaning cylinder that is rotatably driven at a sufficient speed to impart centrifugal forces on the threshed grain to urge the grain through sieve openings during each entire 360 degree revolution of the cleaning cylinder. The cleaning sieves are mounted within axially extending cleaning shoes connected to the rotating cleaning cylinder for individual reciprocatory movement along a generally axial direction inclined inwardly toward the axis of rotation to convey the threshed grain rearwardly and help the cleaned grain pass through the sieve openings. Simultaneously with the rotating of the cleaning cylinder and the reciprocating of the cleaning shoes, a fan blows air through the sieves in the cleaning cylinder to make the unwanted residue airborne for discharge rearwardly from the cylinder, the air also being directed through the threshold grain twice before it is received on the sieves.

Abstract: A combine harvester comprising a threshing and separating mechanism for threshing and separating crop material and a cleaning device for cleaning threshed and separated grain. The cleaning device comprises a grain pan adapted to receive threshed and separated grain from the threshing and separating mechanism and to progressively convey said grain in the direction of the discharge end of the grain pan. A sieve structure is disposed to receive threshed and separated grain from the grain pan and comprises at least one chaffer sieve having a receiving end at a level below the level of the discharge end of the grain pan. Fan means are operable to direct a cleaning air blast to the sieve structure for cleaning grain therein.

Abstract: A combine harvester with a threshing and a separating mechanism for threshing and separating crop material and a cleaning device for cleaning threshed and separated grain. The cleaning device comprises a cleaning fan structure with a fan housing and a fan therein. The fan housing comprises a generally cylindrical body extending transversely of the cleaning device with a pair of opposite end walls and an air inlet provided in each end wall and a further air inlet and an air outlet provided in the cylindrical body and extending transversely of the cleaning device.

Abstract: The invention seeks to reduce loss in combine harvesters by monitoring the distribution of crop material over the grain cleaning mechanism and taking corrective action when the distribution is unfavorable such as by adjusting one or more components of the combine which affect said crop distribution.In one embodiment, temperature-sensitive devices are provided on the louvres of the chaffer sieve of the grain cleaning mechanism and the output signals of the devices are applied to a control circuit which produces a command signal which can be used to control the speed of a fan of the cleaning mechanism or to adjust the position of baffles in the fan outlet duct.