A combine harvester has a driving shoe arrangement. The driving shoe includes a preparation pan and one or more sieves, coupled to a drive mechanism for driving a reciprocating movement of the pan and sieves. The stroke of the reciprocating movement of the pan and/or sieves is adjustable, through the application of a drive mechanism including one or more pivotably mounted support arms for supporting the pan or sieve, and a drive arm connected to one of the support arms through an adjustable connection link. The adjustable connection link can be a variable length actuator whose length determines the stroke of the pan or sieve. The stroke of the pan or sieve can be adjusted during a harvesting run, thereby allowing a fast adjustment to changing external conditions such as the slope of the terrain.
