Elijah McCoy is credited for inventing a self-regulating lubricator for steam engines in 1872 with U.S. Patent number 129,843. This is the first among his 52 patented inventions. The "graphite lubricator" is regarded as his greatest invention; it is a lubricator for cylinders of "superheater" train engines and uses powdered graphite in oil. His other popular inventions include an improved folded ironing table and a lawn sprinkler.
Elijah McCoy was an African American mechanical engineer who eventually landed a job at the Michigan Central Railroad as a train fireman and oilman. While on the job, he saw a problem concerning the need for the train to stop periodically to lubricate its steam engine and moving parts to prevent overheating. His invention, the self-regulating lubricator, resolved the problem by using the steam pressure in the cylinders to automatically pump oil to the engines when it is needed even while the train was in motion. This also prevented the corrosion of the metal cylinders and pistons by the hot, high-pressure steam. The success of his invention revolutionized the transportation and manufacturing industry from 1850 to 1930. Improved versions of his invention were used not just for steam trains, but also for steam engines in factories, mines, ships and construction equipment. The term "Real McCoy" became popular because when machinists and engineers wanted to buy his genuine lubricators, they said they wanted the "Real McCoy," or the real thing.