is fully lowered see fig2 blind system 110 will be at its maximum height h max and each spring 136 138 will be at its maximum length l max to open blind system 110 bottom rail 116 is manually urged toward head rail 114 when this occurs slats 112 will begin to accumulate on bottom rail 16 and any resulting slack created in lifting cords 120 and 122 will be immediately taken up by spring motor and storage unit 130 as a result of the free ends 144 and 146 of springs 136 and 138 moving away from each other when bottom rail 116 is fully raised see fig3 blind system 110 will be at its minimum height h min and each spring 136 138 will be at its minimum length l min from fig2 and 3 it can be seen that the height of blind system 110 will always vary in a predetermined manner in relation to the length of each spring 136 138 in the embodiment of fig2 and 3 each cord 120 122 is looped one time in spring motor and storage unit 130 in particular cord 120 is looped once about free end 146 and cord 122 is looped once about free end 144 cords 120 and 122 may be two portions of a single cord having its ends operatively coupled to bottom rail 116 or alternatively cords 120 and 122 may be separate cords connected together at a point between free ends.