Elijah McCoy and Clarence B. Hodges’s patent for a “Lubricator”, No. 418,139, describes an automatic, safety-focused lubricator. Patented on December 24, 1889, this invention was a significant improvement on their previous designs, specifically addressing the problem of a broken sight-feed glass.
The key innovations included:
- Automatic Check-Valve: The lubricator featured an automatic check-valve located in the oil-exit passage just after the sight-feed glass. This valve was designed to open freely to allow oil to flow to the engine but would instantly close with any back-pressure. In the event of a sight-feed glass breaking, the valve would automatically seal the pipe, preventing the escape of steam and oil.
- Pulsation-Reducing Nozzle: A restricted nozzle was placed in the oil-exit passage to regulate the flow of steam from the equalizing pipe. This neutralized the pressure pulsations that could disturb the oil and water in the sight-feed glass, leading to a more consistent feed.
- Auxiliary Oiler: The design included an auxiliary oiler that could be used to inject oil into the system when the engine’s throttle was closed. This was a valuable feature for maintenance and for ensuring that the engine remained lubricated even when it wasn’t running.
Societal Impact and Legacy
This patent is a perfect example of McCoy’s genius. He not only invented a better product but also solved a complex engineering problem that led to massive economic savings.
- Safety and Reliability: The automatic check-valve was a major safety innovation. A broken sight-feed glass was a dangerous event, and a valve that automatically sealed the pipe was a crucial improvement. This design also protected the lubricator itself from backflow and other common issues.
- Industrial Efficiency: The pulsation-reducing nozzle and auxiliary oiler ensured a more consistent and efficient lubrication process. This reduced oil waste and improved the overall performance and longevity of the engine.
- The “Real McCoy”: This patent is part of the story of the origin of the phrase “The Real McCoy”. The superior quality, safety features, and reliability of his lubricators made them far more desirable than the numerous imitations on the market, and engineers insisted on using the authentic product.
- The Inventor’s Legacy: Elijah McCoy, a brilliant African American inventor, was a central figure in American industrial innovation. His work was foundational to the development of the railroad system and factory machinery.
