| 摘要 |
PROBLEM TO BE SOLVED: To mechanically return a brake without electric control and to prevent a return wire from being damaged as much as possible.SOLUTION: When a lower back plate 4b at a lower end of a shutter curtain falling by its own weight hits against an obstacle, a rotary lock member 11 rotates to restrict a rotary drum 10 from rotating and then to restrict a return wire W3 stored therein from being drawn out, and return wires W2, W3 restricted from being drawn out move operation means to return a brake. After the obstacle is removed, the lower back plate 4b moves down to release the rotary lock member 11 from being locked, and the return wire W3 can thereby be drawn out, and the brake having returned on detecting the obstacle is released to make the shutter curtain falls again by its own weight. |
