a cordless , balanced venetian blind or shade with a constant , or a variable force spring motor includes conventional window covering components without the outside hanging lifting cords or cord locking mechanisms . one or more spring motors are employed . a cord spool , in the preferred embodiment , is coupled to one of the spring drums to serve to wind the cords to cause the blind to be raised or lowered , simply by manipulation of the bottom bar of the blind system . due to the spring forces , the system compensates for the increasing weight on the cords as the window covering is raised and for the decreasing weight as it is lowered .