Obed Hussey patented a mechanical reaper in Ohio in 1833. Robert McCormick's son Cyrus McCormick patented a competing reaper design in 1834, and Cyrus McCormick himself later claimed the machine was actually invented in 1831, which would predate Hussey's patent. The two designs competed in the marketplace for decades and were the subject of several lawsuits.
What would resolve this A verified, independently documented date for the McCormick reaper's true first working version would settle whether Hussey's filed 1833 patent or McCormick's disputed 1831 claim has real chronological priority; no such independent record has been produced.
OpenHistory of TechnologyWikipedia contributors, Reaper (Wikipedia)