US Patent 7357240 Conveyor apparatus

A conveyor apparatus comprises step chains which couple a plurality of steps such that the steps, and driving units which drive the chains. Each of the driving units comprises a power unit comprising a motor, and a driving machine including pulleys and belts that reduce a rotation speed of the motor so as to meet a required reduction gear ratio and transfer the rotation speed to the chains, and a pair of right and left driving mechanisms that convert a rotary movement transferred from the machine of the power unit via an eccentric shaft into a movement of rocking units, and apply a propelling force to the chains via pin rollers provided at any one of sides of the rocking units and the chains and gears provided at the other side of the rocking units and the chains to engage with the rollers.