TODAY IN AUTOMOTIVE HISTORY - AUGUST 22, 1950
Ralph Teetor (August 17, 1890 – February 15, 1982) was a prolific (and blind) 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 became blind at age five in an accident, but as a grown man he preferred never to discuss his disability. He graduated from the University of Pennsylvania with a degree in mechanical engineering in 1912.
Teetor's highly developed sense of touch proved helpful in developing a technique for balancing steam turbine rotors used in torpedo-boat destroyers. Dynamic balancing of large components had puzzled others before Teetor solved the problem.
Teetor was inspired to invent cruise control one day while riding with his lawyer. The lawyer would slow down while talking and speed up while listening. This rocking motion so annoyed Teetor that he was determined to invent a speed control device. In 1945, after ten years of tinkering, Ralph Teetor received his first patent on a speed control device. Early names for his invention included "Controlmatic", "Touchomatic", "Pressomatic" and "Speedostat", with "Speedostat" becoming the trademark name. The common name became "Cruise Control". The Perfect Circle device wasn't used commercially until Chrysler introduced it in 1958.
The throttle was controlled by a bi-directional screw drive electric motor, the two connected during use by an electro magnet. A 12v post would stay nearly centered between two throttle mounted electric contacts, one for turning the motor's screw for more throttle, the other for less. The floating post would "guide" the motor (and throttle and vehicle speed) with input from 1) sprung leveraged spinning weights driven from the transmission's speedometer cable, and 2) a counter-spring tension set by a cable from a dial near the steering wheel. This first-mass-marketed design was the industry standard for just over a decade (GM changed to vacuum-actuator/turn-signal-engage-button in 1969, though still a "Speedostat" product).
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