Timeline

1929 – Duncan starts manufacture of yo-yos.

1930 -- July 22 -- Flores Yo-Yo Corporation obtained registration of the trademark "Flores Yo-Yo."

1932 – Nov. 1 – Donald F. Duncan Sr obtains registration for trademark of “Genuine Duncan Yo-Yo.”

1937 – Royal Tops Manufacturing, formed by a Filipino who had been working for six years at Duncan as a yo-yo demonstrator. The company started producing yo-yos and puts that word on its packages.

1946 -- Duncan Plant Opens in Luck 


1961 -- Duncan files lawsuit against Royal claiming trademark violation on "Yo-Yo"

1962 -- New Employee Newsletter Warns of Foreign Yo-Yos and Seeks Cost Cutting

1965 -- March 3 -- Federal appellate court rules against Duncan, says yo-yo is generic term that any company use. 

1965 -- May 4 -- Appellate court denies Duncan rehearing 

1965 -- May 28 -- Involuntary petition of bankruptcy filed against Duncan.

1965 -- Luck Plant Closes. Exact date to be determined.
 
1967 -- Federal Appeals Panel Rejects Duncan trademark counterclaims.