Internal mechanism crank roller blinds

It is the component numbered seven internal mechanism crank system role cranking, when the movement is given by the front of the box. The mechanism frame is square. Available in three versions 1: 5, 1: 8 and 1:11 which is the rotation axis ratios and crank. For example the ratio 1:11 mean that for every 11 turns of crank makes one rotation axis of the roll that results in smoothed motion roll during the descent or the rise and to avoid damage. The heavier you roll the better to choose a higher gear for smoother operation.