| 摘要 |
A covering for an architectural opening includes a head rail, a bottom rail with a take-up roller therein and an intermediate rail with both the intermediate rail and bottom rail suspended from the head rail, a fabric material interconnecting the intermediate rail with the bottom rail and being adapted to be wrapped around the roller in the bottom rail, said fabric including a pair of vertically oriented sheets that are horizontally spaced by a plurality of vertically spaced horizontal vanes with the vanes being movable between open and closed positions by opposite vertical movement of the sheets of material. In a first embodiment a first control system is provided for raising and lowering the bottom rail and a second control system for raising and lowering the intermediate rail as well as tilting the intermediate rail to effect an opening or closing of the vanes. In alternative embodiment, the bottom rail is controlled with a spring balanced system so that it remains in any position in which it is normally set.
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