| 摘要 |
A braking device for use in a spring-motor type roller blind comprising cam and brake means interposed between a rotatable tube and a fixed shaft in substitution for a centrifugal clutch. The means has a brake drum mounted on the fixed shaft, a coil spring brake mounted on the brake drum, a cam sleeve mounted on the brake drum and formed with a Y-shaped cam groove, the coil spring brake having one end fixed to the cam sleeve and the other end disposed under the bottom part of the Y-shaped cam groove, and a cam casing integrally mounted in the tube and provided with a cam pin for engagement with the cam groove. The cam pin relatively moves along the cam groove and pushes either of the opposite ends to loosen the coil spring brake when the screen is drawn and when it is released after drawn from a position except the uppermost position and fasten the same on the brake drum when it is released after drawn from the uppermost position.
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