Window Covering Having a Lift System Utilizing Conical Spools

摘要

A window covering has an upper rail and lift cords that extend from the upper rail to window covering material. The lift cords are wound onto respective conical spools when the window covering material is retracted and is unwound from the spools when the window covering material is extended. The conical spools move along a portion of the length of a shaft that couples the conical spools to a spring motor when the window covering material is moved from a retracted position to an extended position. The lift cords are unwound from the spools so that a segment of the lift cord that extends from the spool through a hole in the headrail is positioned adjacent a portion of the spool that has a smaller diameter when the window covering material is in the extended position as compared to when the window covering material is in the retracted position.