ALEXANDRIA, Va., July 16 -- United States Patent no. 12,357,867, issued on July 15.
"Chest expander" was invented by Jian Xu (Zhejiang, China).
According to the abstract* released by the U.S. Patent & Trademark Office: "A chest expander comprises a shell, a rotating shaft, a winding storage wheel, an elastic member, and a pull strap, further comprises a resistance adjustment mechanism, and the resistance adjustment mechanism comprises a resistance wheel, an arc-shaped base strap, and a friction plate, wherein the resistance wheel is arranged on the rotating shaft, the arc-shaped base strap is arranged opposite to a peripheral surface of the resistance wheel, and the friction plate is arranged on an inner surface of the arc-shaped base str...