Roller blind winding mechanism - has brake on pulley or cord counteracting torque from blind weight

摘要

The mechanism winds and unwinds a roller blind, having a pulley in a frame engaging with a winding spindle, and in turn engaged by balls on a cord or chain. Brakes are included to prevent the blind unwinding of its own accord. One or more braking devices (13,14,15) act on the pulley (6) and/or the cord (5) with a predetermined pressure, the total braking force thus exerted being greater than the torque from the weight of the blind on the pulley. The device can have a component engaging with a recess in the pulley or between balls on the cord, and thrust free against spring action when torque is applied greater than that resulting from the blind weight.