| 摘要 |
A cord driving mechanism for a blind is described, which comprises a cord driving pulley having a circumferential, radially outward-facing groove comprising a plurality of nips, the nips defined by formations which are disposed opposite one another on respective sides of the groove and are positioned so that the path of a cord around the pulley is relatively straight and so that the cord is substantially unconstricted in the regions between the nips; and a shoe, relative to which the pulley rotates, which surrounds at least part of the circumferential groove in the pulley. A cord passes around the pulley, in the space defined by the circumferential groove and the shoe. The cord is retained in the groove by contact with the shoe. The dimensions of the groove, the spacing between the groove and the shoe, and the size of the cord provide a desired resistance to rotation of the pulley and a desired maximum load which can be exerted on the cord.
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