The aim of the invention is to provide a sieve jigger comprising a sieved-product rocker that can be pivoted upwards and downwards, whose lifting displacement and/or lifting frequency can be controlled beyond previously accepted limits and which does not require vibration dampers that are subject to wear. To achieve this, the sieved-product rocker is operated by means of a lifting and braking cylinder comprising an integrated measuring device for the displacement of the cylinder piston and a working chamber, to which a hydraulic-oil supply and evacuation conduit is connected, said conduit containing an integrated proportional control valve. The lifting and braking cylinder interacts with the proportional control valve by means of a displacement sensor and a governor in order to control the displacement upwards and downwards and thus the lifting height and/or the lifting frequency of the rocker.