ALEXANDRIA, Va., June 9 -- United States Patent no. 12,285,647, issued on April 29.

"Rotation exercising ball structure swinging smoothly" was invented by Yu-Lun Tsai (Taichung, Taiwan).

According to the abstract* released by the U.S. Patent & Trademark Office: "A rotation exercising ball structure includes two shells, two pivot seats, a weight unit, and two handle protecting members. The two shells are combined to construct a hollow ball. Each of the two shells has a space. Each of the two pivot seats is formed on the space and has a through hole. The weight unit includes a mandrel, a rotation member, two bearings, and a weight. The mandrel has two ends each secured in the through hole of one of the two pivot seats. The rotation member h...