ALEXANDRIA, Va., June 25 -- United States Patent no. 12,338,682, issued on June 24, was assigned to Mingyang Windeco Technology Corp. (Zhenzhou, China).
"Compound spring bar" was invented by Nianqing Zhang (Henan, China), Shehua Wei (Henan, China) and Peilun Qian (Henan, China).
According to the abstract* released by the U.S. Patent & Trademark Office: "A compound spring bar includes a compound spring having one end fixed and the other end rotating as a curtain fabric opens and closes, where the compound spring includes at least two springs with different diameters, the springs are nested in layers according to their diameters, adjacent springs are connected in series, and all the springs form a combined spring; and free ends of an innerm...