Abstract: A natural frequency conveyor includes a tray, base, drive system, spring assembly and drive controller for delivery of articles. The drive system includes pairs of identical first and second electromagnets having the respective pole pieces. Preferably the pole pieces of the respective second electromagnets are mounted to the tray, and the pole pieces of the others to the base, so that the second electromagnets so as to the tray are movable in the direction of action of the drive system when energized by a three-phase electricity to be efficient in operation of the conveyor. The spring assembly includes sets of flat springs, which are mounted to the respective tray and base to thereby force the tray to move back when the drive system is not energized. This results in an oscillating movement of the tray according to the natural frequency of the assembly.

Abstract: A drive and drive controller for a vibratory conveyor, wherein the drive comprises a pair of pole pieces offset along a direction of action of the drive, and moveable in the direction of action of the drive when energized by a power signal. Preferably, one of the pole pieces is mounted to a tray portion, and the other to a kinetic balancer portion, of the conveyor. The power signal comprises a series of pulse trains of controllable frequency and duration, whereby the drive unit may be vibrated at a controllable frequency and amplitude so that the vibratory conveyor may be readily tuned to optimal performance. Optionally, the voltage level of the power signal may be reduced by an autotransformer in series with the power signal to independently control the power level.