Abstract: A step-plate mechanism is provided for a door-opening/closing device that is powered by the downward movement of a step plate caused by a stepping force of a pedestrian, with the step plate being disposed on a floor at both the front and back of a door as seen by a pedestrian, including a return mechanism is provided to bias the step plate, which moves downward by the stepping force of the pedestrian, to return to its original position after the pedestrian passes.

Abstract: To further reduce the space required for installation, and to facilitate installation of a device for opening and closing a door by the stepping force of a pedestrian, the door-opening/closing device includes a step plate (2) provided with multiple bearings, a link (5) whose one end is coupled to a bearing (6) of the step plate (2), with the bearing (6) disposed in a metal part fixed on the floor and coupled to the other end of the link (5). The step plate (2) remains horizontal when stepped on, and moves downward in an arcuate manner in the direction in which the pedestrian is walking. The door (1) is opened and closed using this displacement (i.e., the step plate's downward movement) as a motive force. The return mechanism of the step plate (2) is composed of a link extender in which the other end side of the link (5) is extended in the direction opposite from the step plate (2), and a weight (7) that is axially supported on the extending-end part of the link extender.