| 摘要 |
<p>A window covering system comprises a plurality of slats located between a head rail and a bottom rail. The bottom rail is connected to the head rail by a pair of lifting cords extending through the slats. A first spring motor and storage device is located in one of the head rail and the bottom rail. The first spring motor and storage device includes at least one extension spring having a first end that is fixedly secured in the head rail or bottom rail and a second end that is free to move within the head rail or bottom rail and a second end that is free to move within the head rail or bottom rail. At least one of the lifting cords is looped around the free end of at least one of the extension springs to that movement of the bottom rail in a vertical direction causes a corresponding movement in the second end of the extension spring in a direction along the longitudinal axis of the head rail or bottom rail. A method for balancing a window covering system using a pair of extension springs is also disclosed.</p> |
