Abstract: A mobile screening apparatus can be vibrated by two similarly-constructed vibration units that are mounted on or near the front and rear walls of the box that contains the vibrating screen assembly. Each vibration unit comprises an hydraulic motor having a stub drive shaft and a circular eccentric cam or weight carried on the shaft. The screen assembly has connections to the circular cams or weights, whereby motor rotation vibrates the screen assembly. The use of stub shafts eliminates whipping shaft motions associated with conventional elongated shafts spanning the screen assembly.

Abstract: A mobile screening apparatus for gravel and other aggregates includes a three sided box adapted to rest on the ground surface. A vibrating screen is located above the box in a tilted, or sloped condition, so that gravel deposited on the screen is in a fluidized condition. Relatively fine gravel particles (stones) pass downwardly through the screen into the box. Two upwardly divergent trough walls are rigidly secured to side edges of the screen to guide gravel particles onto the screen. A rotary motor is mounted on the undersurface of the screen to rotate an elongated shaft that acts as a counterweight to oscillate the screen in a generally vertical direction. The motor and elongated counterweight shaft are exposed so as to be readily accessible for inspection or maintenance purposes.

Abstract: A mobile screening apparatus for gravel and other aggregates includes a three sided box adapted to rest on the ground surface. A vibrating screen is located above the box in a tilted, or sloped condition, so that gravel deposited on the screen is in a fluidized condition. Relatively fine gravel particles (stones) pass downwardly through the screen into the box. Two upwardly divergent trough walls are rigidly secured to side edges of the screen to guide gravel particles onto the screen. A rotary motor and counterweight system is mounted on the undersurface of the screen to oscillate the screen in a generally vertical direction. The motor and counterweight system are exposed so as to be readily accessible for inspection or maintenance purposes.