Purpose: Automatic lubricators are devices used to supply lubricating oil to the cylinders of steam engines, and sometimes to their bearings and axle box mountings.
Types:
Displacement lubricators
Hydrostatic lubricators
Mechanical lubricators
Historical Development
Elijah McCoy's Invention
Inventor: Elijah McCoy, a Canadian who became a U.S. citizen after moving to Michigan.
Patent Year: 1872
McCoy patented an automatic lubricator that used piping to deliver oil by gravity from a central reservoir to required locations.
Advancements in Lubricator Design
Sight-Feed Lubricators (circa 1887):
Introduced a sight glass in the cab to allow observation of the oil feed rate.
1898 Patent:
Added a glass tube mounted below the reservoir for monitoring delivery rate.
Included a bypass pipe to prevent blockage of the main feed.
Significance
The development of automatic lubricators, particularly McCoy's innovations, were significant in the improvement of steam engine efficiency and reliability.