Patent ID: 7416658
Filing Date: 2008-08-26
Classification: B01D,C02F,E02B,Y10T

Abstract:
1. An elliptical motion drive device for use in a step screen comprising an elliptical motion drive unit connected to a drive shaft that is rotated via a drive motor and a reduction gear, the drive unit operating to elliptically move movable lattice plates connected to a movable frame of the step screen, the elliptical motion drive unit comprising: first and second guide rails configured to be affixed to the movable frame, the first and second guide rails being formed in different directions from each other; a first eccentric wheel eccentrically coupled at one side thereof to the drive shaft to eccentrically rotate and move along the first guide rails upon receiving a rotating force of the drive shaft; and a second eccentric wheel eccentrically coupled at one side thereof to the drive shaft to eccentrically rotate and move along the second guide rails upon receiving the rotating force of the drive shaft, the first and second eccentric wheels being eccentric to each other.