The conventional escalator keeps the operation speed, when passengers move at any traveling position. If the speed at the inclined middle part is faster than the riding and leaving position, such a system can not only achieve short traveling time, but can also offer safety ride to elderly and disabled person. Therefore, the concept to change the speed partially in the traveling range has a great advantage to the passenger. The idea for speed change mechanism has already been established to a moving walk, which is horizontal one dimensional motion. However there is no actual two dimensional system with the speed change mechanism, due to its complex configuration. This paper shows a new speed change mechanism for an escalator, which is a typical moving mechanism for the two dimensional service, and shows a design method of the mechanism to fill the acceleration specification. The proposed mechanism can be achieved by a simplified link and cam mechanism to realize a smooth speed change between the inclined and horizontal zone. The simplified design method based on difference equation can evaluate the transient motion of the escalator step, which is strongly affected by the geometric constraints. The simulation result and an experiment with a 5m-tall prototype show its design validation for the smooth ride comfort even in the area of the speed change.
