On May 3, 1983, Harrigan was granted a US patent for his original levitation device based upon this phenomenon he discovered.
[1][2] Independent of Harrigan, a Pennsylvanian inventor named Joseph Chieffo made the same discovery in 1984 employing a flat base magnet, a geometry that proved a significant change over his predecessor's patented design which relies upon a dish shaped mounting of magnets for the base.
Chieffo's design, publicized in a 1991 edition of the periodical "Magnets In Your Future",[3] further differed from Harrigan's in its incorporation of an un-weighted top.
[4][5] Harrigan's technology, either solely or in conjunction with Chieffo's published flat-base variation, provided the basis for the development of a series of mass marketed levitating toy tops sold predominantly in the United States under the brand name, 'Levitron' and in other countries from different manufacturers under their brand names (e.g. UCAS in Japan).
[8] Inclined or horizontal spin axis levitation is accomplished by superposing a "macro-trap" on the precessional "micro-trap" first described by Sir Michael Berry[9] and Simon, Heflinger and Ridgway.