In the Fall 2004 edition of the Vertex Angle we asked "How many US patents were granted to Thomas Edison?"
a) 752, b) 979, c) 1009, d) 1093, or e) 1624
The correct answer is: d) - 1093 patents
The first of Edison's 1,093 U.S. patents issued on June 1, 1869 and the last on May 16, 1933, almost 2 years after his death. He filed an estimated 500 to 600 unsuccessful or abandoned applications as well.
In his early years, Edison did not always rush to his patent lawyer with an invention, especially if there was little competition for the invention or he was unable to pay the various fees required for an application. In a few cases, Edison removed some of the claims from an original application and subsequently filed a new application to cover those claims. The issue date of the subsequent patent would have been considerably later than that of the original application, even though the patent pertained to designs from the earlier patent filing. At the peak of his career in 1882, Edison filed for over 100 patents.
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