Portable crushing and screening plant

In a mobile material crushing and screening plant having an elongated frame and wheels mounted on and in supporting relation to the frame, the combination comprising:

• a first screening device, a primary crusher, a secondary crusher and a second screening device mounted on said frame in longitudinal sequence in the order recited,
• an endless belt conveyor on said frame having a main endless belt with a working run having a longitudinal extending portion extending horizontally in the elongated direction of said frame beneath said screening devices and crushers, said working run having a curved segment curving upwardly in an arc from beneath said second screening device, thence adjacent the receiving end of said second screening device, said receiving end being more remote from a selected end of said frame than the discharge end of said second screening device, said curved segment of said working run of said endless belt terminating above said receiving end of said second screening device, said conveyor including an endless cover belt having a working run cooperatively engaging said curved segment of said working run of said main endless belt,
• said first screening device being operable to separate the material deposited thereon into fines and oversize material and to feed the oversize material to said primary crusher and the fines to said working run of said main endless belt disposed therebelow,
• said primary crusher being operable to crush said oversize material and discharge its output onto said working run of said main endless belt,
• said secondary crusher discharging its output onto said working run of said main endless belt,
• said belt conveyor being operable to convey the material received from said first screening device, said primary crusher and said secondary crusher and discharge it directly onto said receiving end of said second screening device,
• said second screening device being operable to separate material delivered thereto by said belt conveyor into oversized material which it delivers directly to said secondary crusher and fines which do not require additional crushing which it delivers to discharge means,
• said secondary crusher receiving exclusively said oversize material from said second screening device and discharging its output onto said working run of said main endless belt and
• a generally upright support structure for supporting a major portion of said curved segment of said working run of said main belt, said support structure having a lower section secured to said frame and an upper section pivoted on a transverse axis at its lower end to the upper end of said lower section, said upper section being swingable from an upright operating position downwardly about said transverse axis to a lowered transport position.