Patent ID: 7422116

Claim:
A self-propelled screening apparatus which comprises: a chassis; a pair of endless tracks supporting the chassis; a superstructure comprising a prime mover arranged to provide motive power to operate the endless tracks, said superstructure being rotatable relative to the chassis about a rotational axis extending upwardly from the superstructure; and a screen box mounted on the superstructure, said screen box being pivotally adjustable relative to the superstructure about a pivot axis extending upwardly from the superstructure, said pivot axis of said screen box being additional and independent to the rotational axis by which the superstructure is rotatable relative to the chassis, said screen box being mounted on the superstructure such that the screen box is located directly over at least a portion of the superstructure when oriented with the weight of the apparatus borne by the endless tracks, said screen box having an input for receiving a supply of bulk material, at least one screen deck for screening the bulk material, and an output for discharging screened material; in which the prime mover is disposed in the superstructure such that the prime mover and the screen box are arranged on opposite sides of the rotational axis of the superstructure, to provide a stable weight distribution, wherein the screen box is mounted on the superstructure to pivot about the pivot axis so that the discharge position of the output of the screen box is adjusted relative to the rotation axis of the superstructure.