Vibrating screen

A vibrating screen comprising:

• at least one screen deck defined between two screen deck sidewalls, the screen deck configured to support bulk material;
• a mechanical vibrator mounted to the screen deck sidewalls and having two transversal shafts which rotate at the same rotation speed and in opposite directions, each shaft having end portions, each end portion carrying at least one eccentric weight;
• at least two beams extending transversal to a longitudinal axis of the vibrating screen and each having opposite ends fixed to one of the screen deck sidewalls;
• wherein the end portions of the shafts are each supported by a plurality of bearings mounted to one of two bearing cases which are each removably fixed to the beams such that each of the end portions is adjacent to one of the end portions of the other one of the shafts, wherein each of the bearing cases includes a pair of opposite bearing sidewalls and wherein each of the eccentric weights is located externally to the bearing sidewalls;
• wherein a total mass of the at least one eccentric weight carried on each end portion of one of the shafts is different than a total mass of the at least one eccentric weight carried on each end portion of the other one of the shafts;
• and
• wherein said two shafts rotate in determined phases to impart elliptical movement to the screen deck, the major axis of the elliptical movement having a forward and upward inclination, to transport the bulk material along the screen deck.