| 摘要 |
PROBLEM TO BE SOLVED: To turn a turning body by low tensile force and to prevent for a rope member to make no effective use of a space around the turning body. SOLUTION: A door panel 13 can be turned with a bearing 14 as the center. A traveling body 25 can be approached/separated from the bearing 14 by the circumferential moving operation of the circumferential moving chain 23. One end of a tension chain 26 is connected to the door panel 13, and the other end thereof is connected to the traveling body 25. When the door panel 13 is in a closing position, the traveling body 25 is approached to the bearing 14, and a tension angle of the door panel 13 by the tension chain 26 is reduced to approximately 0 degree. When the door panel 13 is turned to an open position, the traveling body 25 is moved in the direction of separation from the bearing 14 to increase the tension angle. |
