Patent ID: 7296671

Claim:
A drive system for escalators having steps or moving walkways having pallets, comprising: at least one drive motor; at least one drive chain driven by the drive motor and comprised of a plate link chain, the drive chain having such a pitch that a maximum of two links are used for each step or pallet; a reversing element for the drive chain; means for minimizing a polygon effect which occurs during entry and reversing of the chain at the reversing element, the means for minimizing including at least one device for actuating one of the drive motor, the reversing element or the drive chain with a non-constant rotational speed or velocity, wherein the device comprises a power supply unit that drives the drive motor with a non-constant rotational speed; a control unit that cooperates with the power supply unit; and at least one sensor that detects a phase position of the reversing element and transmits measured phase values to the control unit for controlling the power supply unit.