Abstract: An improved rotary vibrator unit of the type comprising a first member adapted to be mounted on a shaft for rotation thereon or therewith, a mass mounted on said first member and adapted to be moved under the influence of centrifugal force during rotation of both said members and said mass in a radial direction relative to the axis of rotation thereof to unbalance the unit and cause it to vibrate, said unit further including resilient means adapted to provide a first resistance to radial movement of said mass through a first range of angular motion of said unit and including means providing a second resistance in addition to said first resistance during a second range of angular motion whereby the resistance to radial movement of said mass has a non-linear characteristic over the full range of angular motion of said unit.

Abstract: A vibratory feeder, conveyor, separator, screen, or other vibratory equipment used in materials handling and related fields of the tuned two mass type in which one mass is an imbalance generator of the type using eccentric weights on a rotating shaft uses helical coil springs for coupling the imbalance generator to the trough or the like without clamping of the ends of the springs or constraining them to remain parallel to each other. Decoupling of the lateral oscillatory forces from the trough is achieved by using at least two pairs of collinear springs, one of each pair on each side of a wall member secured to the trough, and each held in compression between the wall member and a pair of vibrator plates held in fixed spaced apart relationship on each side of the wall member. The imbalance generator is secured to one of the vibrator plates so as to be well outside the spring system thus giving a low natural lateral frequency to the two mass system.