| 摘要 |
A cord spool for an architectural covering, such as a Venetian blind, having a rotatable central shaft for opening and closing the covering. The cord spool includes a circumferential surface, about which an operating cord can be wound that can be driven in opposite directions to open and close the covering. The spool is arranged so as to regulate or prevent an F(pull) gradient when pulling on one end of the operating cord to open the covering; and has a variable coupling connected to the central shaft and the circumferential surface for automatically actuating the regulating or preventing operation when the torque on the central shaft, exerted by the window covering, is greater than the torque on the circumferential surface, exerted by the operating cord as it is being pulled to open the covering.
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