| 摘要 |
A cordless retractable shade including an operating system for the shade that varies a biasing force of a spring to counterbalance the shade. The bottom rail of a retractable shade can be raised or lowered, and due to the operating system remains in any selected position of the covering between fully extended and fully retracted, without the use of operating cords. The system includes a method of negating and reversing the spring bias effect at a strategic position whereby the flexible vanes of the shade can be adjusted between open and closed. |
