Vibrating conveyor.

The blue part vibrates in two directions (vertical and horizontal) under centrifugal forces caused by the orange eccentrics and move the material (red).

Angle A between the two eccentrics affects vibration characteristics.

A = 0 deg. for this case.

The green line is locus of a point on the blue part (nearly a proper ellipse)

No vibration if A = 180 deg.