Patent model
On July 31, 1790 inventor Samuel Hopkins of Pittsford, Vermont became the first person to be issued a patent in the United States. His patented invention was an improvement in the "making of Pot Ash by a new apparatus & process." These earliest patent law required that a working model of each invention be produced in miniature.
Ukelin
The history of the ukelin is hard to trace, since there were several instruments resembling the ukelin that were produced in the 1920s. Paul F. Richter filed the first known ukelin patent in December 1924, it was granted in April 1926. The Phonoharp Company, which merged with Oscar Schmidt, Inc. the same year, began producing ukelins in 1926. However, an instrument greatly resembling the ukelin had had its patent filed in 1923, a year before Richter filed his; yet the patent, filed by John Large, was not granted until after Richter's patent had already been given. Another similar instrument had a patent filed by Walter Schmidt in 1925. Because of these patents filed one after the other it is unclear who really invented the first ukelin.