COMBINE HARVESTER

摘要

A cleaning system for a harvester has a sieve that is moveable by a drive assembly that includes a rotary drive, an eccentric device, a transmission connected to the eccentric device and to the sieve, which transmission cyclically varies the distance between the driving point of the eccentric device and the sieve coupling during each full rotation of the rotatable output shaft of the rotary drive, wherein, due to the cyclic variation of the distance between the driving point of the eccentric device and the sieve coupling, during each reciprocating sieve movement at least one of the accelerating portion of the throw stroke, the decelerating portion of the throw stroke, the accelerating portion of the return stroke and the decelerating portion of the return stroke has a duration that is different from the duration of at least one other of said portions of the reciprocating sieve movement.

主权项

1. Combine harvester comprising
a cleaning system comprising at least one sieve, an associated sieve drive assembly and a sieve coupling, said sieve drive assembly being connected to the sieve by said sieve coupling, wherein said sieve is moveable by said sieve drive assembly to perform a reciprocating sieve movement having a throw stroke and a return stroke, said throw stroke and said return stroke each having an accelerating portion and a decelerating portion, wherein the sieve drive assembly comprises: a rotary drive comprising a rotatable output shaft having a center line, an eccentric device fixedly connected to the rotatable output shaft of the rotary drive to rotate with the rotatable shaft, wherein the eccentric device has an eccentricity and a driving point, the driving point is rotatable around the center line of the rotatable shaft along a circular path having a radius that equals the eccentricity of the eccentric device, a transmission comprising a first end connected to the eccentric device and a second end connected to the sieve coupling, the transmission is adapted to transfer the movement of the eccentric device to the sieve coupling and to cyclically vary the distance between the driving point of the eccentric device and the sieve coupling during each full rotation of the rotatable output shaft of the rotary drive, wherein, due to the cyclic variation of the distance between the driving point of the eccentric device and the sieve coupling, during each reciprocating sieve movement at least one of the accelerating portion of the throw stroke, the decelerating portion of the throw stroke, the accelerating portion of the return stroke and the decelerating portion of the return stroke has a duration that is different from the duration of at least one other of said portions of the reciprocating sieve movement.