US Patent 9238229 Variable conveyor

A vibratory apparatus includes a trough having a first end and a second end, and at least first and second variable amplitude vibration generators coupled to the trough. The first and second variable amplitude vibration generators include at least one variable eccentric weight assembly having a variable center of mass relative to an axis of rotation. The first and second variable amplitude vibration generators have at least a first state wherein an amplitude of a vibratory force generated by the first vibration generator is different than an amplitude of a vibratory force generated by the second vibration generator to cause movement of material in the trough toward the first end or the second end.