| Number | Name | Date | Kind |
|---|---|---|---|
| 1876481 | Wright | Sep 1932 | |
| 2773328 | Fraenkel et al. | Dec 1956 | |
| 2975547 | Greve | Mar 1961 | |
| 3207508 | Klemke | Sep 1965 | |
| 3228140 | White | Jan 1966 | |
| 3256635 | Radovan | Jun 1966 | |
| 3263361 | Bowden | Aug 1966 | |
| 3452470 | Wohlstrom | Jul 1969 | |
| 3858348 | Brown | Jan 1975 | |
| 4086722 | Brown | May 1978 | |
| 4129961 | Parodi | Dec 1978 | |
| 4138798 | Washington | Feb 1979 |
| Entry |
|---|
| "Experimental Fun with the Yo-Yo and Other Science Projects"; Renner, AL G.; Dodd, Mead & Co., N.Y. .COPYRGT.1979. |
| Duncan Yo-Yo "Swivel EZE" Finger Control Accessory. |