Biography

The following section is an excerpt from Wikipedia's Ralph Teetor page on 23 January 2025, text available via the Creative Commons Attribution-ShareAlike 3.0 Unported License.

Ralph Teetor was a prolific inventor who invented cruise control. He was the longtime president of the automotive parts manufacturer The Perfect Circle Co. (acquired in 1963 by Dana Holding Corporation, then sold to Mahle GmbH in 2007) in Hagerstown, Indiana, a manufacturer of piston rings.

Teetor injured his eye at the age of five with a knife. Within a year, he developed sympathetic ophthalmia and became blind in both eyes. As a grown man he preferred never to discuss his disability.

Teetor graduated from Hagerstown High School in 1908. He graduated from the University of Pennsylvania with a bachelor's degree in mechanical engineering in 1912. He returned to the University of Pennsylvania and received a master's degree in engineering around 1930.

After college, he returned to Hagerstown and worked at the Teetor-Hartley Motor Company. He remained with his family's company until they sold their motor division off in 1918. In 1918, Teetor went to Camden, New Jersey to help the New York Shipbuilding Corporation balance turbine rotors on torpedo-boat destroyers in World War I. Teetor's highly developed sense of touch proved helpful in developing a technique for balancing steam turbine rotors used in Navy torpedo-boat destroyers. Dynamic balancing of large components had puzzled others before Teetor solved the problem.

After the war, he returned home. He designed a fluid-operated gearshift that he sold to Bendix in the 1920s. In 1919, he began to work for the Piston Ring Company (later called the Perfect Circle Company), the successor to the Teetor family's piston rings manufacturing division of the Teetor-Hartley Motor Company. From 1919 to 1946, he oversaw the engineering division as director and vice president. He was president of the company from 1946 to 1957. He remained on the board of directors until 1964. Perfect Circle was sold to the Dana Corporation in 1963.

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