Elijah McCoy’s patent for a “Lubricator”, No. 383,745, describes a highly-advanced lubrication system designed to solve a critical problem in locomotives. Patented on May 29, 1888, the invention was a direct improvement on his previous patents and addressed the issue of a clogged oil-exit passage.
The main problem was that if one oil conduit became clogged, oil from both of the lubricator’s sight-feed glasses would be fed into a single cylinder. The engineer, seeing drops in both glasses, would be deceived into thinking both cylinders were being properly lubricated, when in fact, one was being starved of oil.
McCoy’s solution was an ingenious system for visual verification:
- Supplemental Sight-Feed Glass: He added a second, “supplemental” sight-feed glass to the oil-exit conduit at a point after the equalizing pipe had entered the passage. This glass was located closer to the engine cylinder.
- Unfailing Monitor: The engineer could now observe oil drops falling through this supplemental glass. If oil was seen dripping here, they could be absolutely sure it was on its way to the correct cylinder, as there was no other possible outlet for it. If drops appeared in the main glass but not the supplemental one, it immediately alerted the engineer to a clog.
- Auxiliary Steam Pipe: The device also included an auxiliary steam pipe that could be used to send a jet of steam through the oil-exit passage to clear a clog, all without having to stop the train.
Societal Impact and Legacy
This patent is a perfect example of McCoy’s genius for continuous innovation. He didn’t just invent a product; he anticipated and solved the real-world problems that arose from its use.
- Enhanced Reliability and Safety: This invention provided a new level of assurance for engineers. The ability to verify that oil was reaching the correct cylinder and to clear a clog without stopping the train was a major advancement in both safety and efficiency. It prevented costly engine damage and reduced downtime.
- Industrial Innovation: This patent demonstrates McCoy’s deep understanding of the practical needs of the railroad industry and his ability to apply his engineering knowledge to create a truly superior product.
- The “Real McCoy”: This patent is a crucial part of the story of the origin of the phrase “The Real McCoy”. His lubricators, with their superior design and reliability, were so much better than the imitations that engineers insisted on the authentic product.
- The Inventor’s Legacy: Elijah McCoy was a brilliant African American inventor who, despite immense racial discrimination, became a foundational figure in American industrial technology. His numerous patents were critical to the development of the railroad system and factory machinery.
