Patent ID: 9622415
Date: 2017-04-18
CPC Classifications: A01F

Claim:
1. A combine harvester comprising: a cleaning system comprising at least one sieve, an associated sieve drive assembly and a sieve coupling, said sieve drive assembly connected to the sieve by said sieve coupling, said sieve coupling defining a sieve pivot point between said sieve and said sieve drive assembly, 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: 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 or 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.