Patent ID: 7108038

Claim:
A blind comprising a longitudinally extending hollow upper rail having an open left end and an open opposite right end; and a longitudinally extending lower rail having an open left end and an open opposite right end; and a blind material attached to the upper rail and the lower rail and extendable between them and in which the upper rail, the lower rail or both are movable; and a left and a right guide cord extending parallel to each other from the upper rail to the lower rail, the left guide cord entering the lower rail by the left end and the right guide cord entering the lower rail by the right end, and wherein the first and second guide cords cross over in the lower rail such that the left guide cords exits the lower rail at the right end and the right guide cord exits the lower rail the left end; and each guide cord being operatively connected to a cord tensioner; wherein each cord tensioner comprises a compression spring through which the guide cord extends; and wherein both cord tensioners are fixed in the upper rail or the lower rail of the blind each in a dedicated longitudinal position while allowing compression of the spring.