| 摘要 |
PROBLEM TO BE SOLVED: To provide a blind device in which an appropriate braking force is exserted on the downward movement resulting from its own weight of the blind member and it can be surely lowered to the lowermost position and it can be lifted up by a light force when lifting it up. SOLUTION: A rise and fall shaft 8 from which a blind member is hangingly supported can be rotated by an operational cord 7. A clutch means 21 is arranged between the shaft 8 and the cord 7, and the blind member can be lowered by the own weight when the clutch means 21 is released by the operation of the cord 7. meanwhile, a braking device controlling the rotation of the shaft 8 in the gravitational descent resulting from its own weight is connected to the shaft 8. The braking device is provided with a speed increasing ring rows having worm and worm wheel and a centrifugal governor. The braking force is varied so that the braking force is made large when the rotary load acting on the rise and fall shaft 8 is large, and it is made small when the rotary load acting on the shaft is small.
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