Patent ID: 7975748

Claim:
A suspension system for a window covering, comprising: a head rail defining a longitudinal axis; a weighted element; a suspension cord having an end connected to the weighted element; a rotary axle disposed within the head rail and defining a longitudinal axis, the longitudinal axis of the axle and the longitudinal axis of the head rail being substantially parallel; and at least one control module coaxially mounted about the axle and operatively connected with the suspension cord, the control module including: a rotary drum including a spindle formed coaxially and integrally therewith, the rotary drum configured to wind the suspension cord and the axle is assembled through the drum and spindle; a stationary support structure also mounted with the axle and disposed within the head rail; a constant force spring having a first end and a second end, the first end of the spring operatively connected with the spindle of the rotary drum, the second end of the spring being operatively connected to the support structure, the spring being configured to exert a rotational force on the drum causing a raising force opposite to the effective weight of the weighted element wherein the raising force and the effective weight of the weighted element are in substantial equilibrium, the rotational force adapted to be substantially the same amount of force while the window covering is at a raised position and at a lowered position; and each of the rotary drum, the spring, and the support structure being in a coaxial relationship with the axle.