Abstract: The vibrating screen has a frame, a screen box, two pairs of springs supporting the screen box over the frame and a driven eccentric shaft mounted under the screen box. The vibrating screen is characterized by a loading pan affixed to the upper end of the screen box. The loading pan has a central region over the upper springs such that a flexion of the structural members under the loading pan is minimum. The loading pan is wider than the screen box and has sloped sides forming a funnel on the upper end of the screen box to retain the side portions of a load until most of the central portion has been moved to the screen box. In another aspect, each spring has torsion bushings therein, with a pair of arms joining the torsion bushings and forming an angle pointing toward the lower end of the screen box.

Abstract: A portable vibrating screen which has an arched frame, a basket supported on top of the arched frame by springs and a rotatable eccentric shaft for imparting a reciprocal movement to the basket. The arched frame has a vertical tall end, a vertical short end and two spaced apart stringer members joining the upper portions of the tall and short ends. The stringer members define an inclined plane between the tall end and the short end. The tall end has a first pair of spaced apart leg members and a first ballast mounted between the leg members of that first pair. The short end has a second pair of leg members and a second ballast mounted between the leg members of that second pair. An amplitude of a vibration of the basket transmitted to the arched frame is largely absorbed by the mass of the first and second ballasts. In another aspect of the present invention, the eccentric shaft has bearings attached to the basket and to the stringer members for retaining the basket along the inclined plane.