Earliest patent for a yo-yo
Haven & Herrick
first first
United States (Cincinnati)

Although the basic yo-yo design dates back to ancient Greece, the earliest known patent for a toy yo-yo was filed on 20 November 1866 by the Cincinnati, Ohio-based toy company Haven & Hetterick. They called their invention the "whirligig", although they acknowledge that it was a refinement of a traditional toy design known as a "bandelore".

This patent application was cited as "prior art" by Yomega (USA) in their 1999 patent for a ball-bearing-enhanced yo-yo.