Elijah McCoy was granted U.S. Patent 139,407 for an “Improvement in Lubricators” on May 27, 1873. This invention was another refinement of his automatic oiling system for steam engines, building on the principles of his earlier patents. The new design focused on making the lubrication process more efficient and reliable.
Key features of this lubricator included:
- Lubrication on Exhaust: The device was designed to oil the engine primarily when steam was exhausted. This was a crucial innovation, as the vacuum created during the exhaust phase was when oil was most needed to prevent friction.
- Screw-Cap Regulator: The lubricator had a screw-cap regulator at the top of the oil tube. This allowed an operator to precisely control the amount of oil being delivered to the engine.
- Sight-Glass: A significant new feature was a “chamber” with two pieces of glass, or a sight-glass, near the top of the oil cup. This allowed the engineer to see when the oil cup needed refilling without having to open the device. The air chamber between the two pieces of glass prevented them from breaking due to sudden temperature changes.
Societal Impact and Legacy
This patent was another step in a series of inventions by McCoy that collectively revolutionized industrial lubrication.
- Improved Efficiency and Safety: By providing a way to lubricate primarily on the exhaust stroke, the invention delivered oil at the most effective time, improving engine performance and reducing wear. The adjustable regulator allowed for more economical use of expensive oil.
- Enhanced Usability: The addition of the sight-glass was a major step forward in usability. It made the lubricator easier to monitor and maintain, further improving the reliability of the machinery.
- The “Real McCoy”: As with his other patents, this lubricator was superior to the competition, solidifying his reputation. The phrase “The Real McCoy” is widely believed to have originated from engineers who insisted on using his authentic products over the numerous knockoffs.
- The Inventor’s Legacy: Elijah McCoy was a prolific African American inventor who, despite immense racial discrimination, became a central figure in American industrial innovation. His work was foundational to the efficiency and safety of the railroad system and factory machinery of the late 19th and early 20th centuries.
