Window cover system with spring drive arrangement
View Patent ↗A spring drive system useful for window covers is disclosed, which comprises one or more coil spring drives or flat spring drives and the combination whose elements are selected from one or more of a group which includes (1) a band or cord transmission which provides varying ratio power transfer as the cover is opened and closed; (2) gear means comprising various gear sets which provide frictional holding force and fixed power transfer ratios; (3) a gear transmission which provides fixed ratio power transfer as the cover is opened or closed; (4) crank mechanisms; (5) brake mechanisms; and (6) recoiler mechanisms. The combination permits the spring drive force to be tailored to the weight and/or compression characteristics of an associated window cover such as a horizontal slat or pleated or box blind as the cover is opened and closed.
1. A window cover system comprising:
a housing having a longitudinal axis;
an extendible window cover coupled with the housing;
a first cord to facilitate raising and lowering the window cover to any selected position between an extended position and a retracted position;
a spring drive system comprising a pair of spaced apart spring drive spools and at least one flat spring having a storage end coupled to one of the spring drive spools and an output end coupled to the other spring drive spool;
a wind-up spool coaxially aligned with one of the spring drive spools for receiving the first cord, wherein the first cord is wrapped around the wind-up spool for assisting in raising and lowering of the cover when moved to a selected one of the positions; and
a cord pulley system spaced apart from the wind-up spool along the longitudinal axis of the housing, the cord pulley system being configured to accumulate a second cord within the housing and to control a force applied by the spring drive system to the window cover, wherein the spring drive system has no external hand-operated control cord as an input used to raise and lower the window cover.
2. The window cover system of claim 1 , wherein:
the cord pulley system comprises at least two pulleys, and wherein the second cord extends between the at least two pulleys.
3. The window cover system of claim 1 , wherein:
the first cord and the second cord are different.