STEP PLATE MECHANISM FOR DOOR OPENING AND CLOSING DEVICE

To further reduce required installation space and facilitate installation in a device for opening and closing a door that opens and closes by stepping force of a pedestrian. The door opening and closing device comprises a step plate (2) provided with a plurality of bearings, a link (5) having one end coupled to a bearing (6) of the step plate (2), and the bearing (6) disposed in fixed portion of a floor surface and coupled to the other end of the link (5). When stepped on, the step plate (2) maintains a horizontal state and descends while moving in an arcuate manner in the direction of travel of the pedestrian. The door (1) is opened and closed using this displacement as a motive force. The return mechanism of the step plate (2) is composed of an extension link in which the other end side of the link (5) is extended in the opposite direction from the step plate (2), and a weight (7) axially supported on the extension end part of the extension link. The weight (7) rises when a pedestrian mounts the step plate (2) and the step plate (2) descends; and descends under its own weight and causes the step plate (2) to rise when the pedestrian dismounts the step plate (2).