Winding mechanism

An architectural covering and a winding mechanism for controlling the retraction and deployment of the architectural covering, said winding mechanism having a winding element about which at least a portion of the covering is wound and unwound with rotation of the winding element about a first axis of rotation, and a fluid brake for retarding the rotation of the winding element in at least one direction about the first axis;

• the fluid brake comprising a fluid-tight compartment containing a liquid and an impeller and wherein:
• the compartment and the impeller are adapted for relative rotation about a second axis of rotation;
• the compartment or the impeller is operatively connected to the winding element;
• the liquid rotates with rotation of the compartment or the impeller about the second axis;
• rotation of the liquid relative to the impeller or to the compartment in at least a first direction about the second axis is effective to retard the rotation of the winding element in said one direction about the first axis;
• and
• the impeller comprises a hub and a vane mounted on and protruding radially from said hub, and with said vane including a first surface that extends generally radially and substantially parallel with respect to the second axis and, further, wherein said mechanism includes a generally cylindrical inner peripheral wall surface of the compartment and where the impeller includes a plurality of said vanes, each vane being movable, and each vane comprising a second surface of the vane, said second surface being movable towards the inner peripheral wall surface when pressure is exerted by the liquid against the first surface of the vane.