| 摘要 |
A screen-locking device for use in roll blinds of the type having a fixed shaft (11), a screen-roll (15) rotatably fitted on the fixed shaft, a cord-pulley (20) rotatably mounted on the fixed shaft, the device comprising a brake drum (11b) formed on the fixed shaft, a coil spring (24) fitted around the brake drum, the cord-pulley having an opening (22) over the brake drum, the coil spring having the both ends (25, 26) thereof inserted into the opening and crossed in a V-shaped form when axially viewed, a sleeve (17) removably fixed to the screen-roll and rotatably mounted on the fixed shaft (11), a key (18) reversibly fitted on the sleeve and formed with a radill POUND inwardly extending projection (19) on one side of the key. For use with a roll blind having no auxiliary spring-motor, the device produces a large braking force when the key is set one way in which the projection is in a space between the both ends (25, 26). On the other hand, for use with a roll blind with an auxiliary spring-motor (44) to balance the weight of the screen (30), the device produces a small braking force when the key is set the other way in which the projection is out of the space between the both ends. |
