John T. Parsons (October 11, 1913April 18, 2007) pioneered

numerical control Computer numerical control (CNC) or CNC machining is the automated control of machine tools by a computer. It is an evolution of numerical control (NC), where machine tools are directly managed by data storage media such as punched cards or ...

(NC) for

machine tool A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, Boring (manufacturing), boring, grinding (abrasive cutting), grinding, shearing, or other forms of deformations. Machine tools employ some s ...

s in the 1940s. These developments were done in collaboration with his Chief Engineer and Vice President of Engineering, Frank L. Stulen, who Parsons hired when he was head of the Rotary Wing Branch of the Propeller Lab at

Wright-Patterson Air Force Base Wright-Patterson Air Force Base (WPAFB) is a United States Air Force base and census-designated place just east of Dayton, Ohio, in Greene County, Ohio, Greene and Montgomery County, Ohio, Montgomery counties. It includes both Wright and Patte ...

, in April 1946. Together, they were the first to use computer methods to solve machining problems, in particular, the accurate interpolation of the curves describing

helicopter rotor On a helicopter, the main rotor or rotor system is the combination of several rotary wings (rotor blades) with a control system, that generates the aerodynamic lift (force), lift force that supports the weight of the helicopter, and the thrust ...

blades. In 1946, "computer" still meant a punched-card operated calculation machine. In 1948, Parsons' company, "Parsons Corporation" of Traverse City,

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

, was awarded a contract to make the challenging tapered wings for military aircraft; they won the contract because they developed the computer support to do the difficult three-dimensional interpolation for the complex shapes, as well as the 800 steps long production cycle for the wing manufacturing.

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

was one of the subcontractors, as was

MIT The Massachusetts Institute of Technology (MIT) is a private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of modern technology and sc ...

, which took care of the

servomechanism In mechanical and control engineering, a servomechanism (also called servo system, or simply servo) is a control system for the position and its time derivatives, such as velocity, of a mechanical system. It often includes a servomotor, and ...

s. The latter lab boosted the developments of numerical control machining in the following decades, by developing reliable servo control in 1952 and the APT (''Automatic Programmed Tool'') programming language for NC machines. Parsons, however, quickly saw the potential of connecting computers to the machine motors. On January 14, 1958, he received a

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

for a ''Motor Controlled Apparatus for Positioning Machine Tool'' (patent number 2,820,187, filed on May 5, 1952). The initial developments of NC machines, however, had been so expensive that Parsons was fired from his own company because the funding of the MIT developments was too much for the company. Parsons was reinstated as president of the company after royalties on the patent had generated significant amounts of money. (

Bendix Corporation Bendix Corporation is an American manufacturing and engineering company founded in 1924 and subsidiary of Knorr-Bremse since 2002. During various times in its existence, Bendix made automotive brake shoes and systems, vacuum tubes, aircraft ...

was an initial licensee of the patent, in 1955, and eventually bought all the rights to it.) In 1985, Parsons and Stulen received the National Medal of Technology. In 1988 he received an honorary Doctor of Engineering degree from the

University of Michigan The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...

. In 1993, Parsons (but not Stulen) was inducted into the

National Inventors Hall of Fame The National Inventors Hall of Fame (NIHF) is an American not-for-profit organization, founded in 1973, which recognizes individual engineers and inventors who hold a US patent of significant technology. Besides the Hall of Fame, it also operate ...

for inventing numerical control. Parsons died on April 18, 2007, at the Grand Traverse Pavilions. He was 93. He had six children.

References

{{DEFAULTSORT:Parsons, John T. 1913 births 2007 deaths National Medal of Technology recipients People from Detroit