Niels Anton Christensen (16 August 1865 – 5 October 1952) was a Danish-American inventor whose principal invention was the O-ring, the ubiquitous hydraulic seal.
Christensen became a leading draftsman at Fraser and Chalmers in Chicago, a manufacturer of machinery for industry, mining, and transportation. While working in Chicago, he witnessed an accident of a new electric railway, which resulted in two deaths and a number of injuries because the conductor was unable to stop the rail cars in time using the mechanical brake. Christensen decided to design and build a power brake. The Christensen air brake was successfully tested on Detroit's streetcar system, but a downturn[colloquialism] of the economy prevented Christensen from manufacturing and marketing the system.
He worked briefly on electrical systems for Chicago's Columbian Exposition and then was hired by the E. P. Allis Company of Milwaukee. While at E. P. Allis, he continued to develop his air brake for electric rail cars and streetcars. In 1896 he obtained financial backing that allowed him to make an experimental test apparatus. He also secured patents on the new valve mechanism. In early 1897, he founded Christensen Engineering Company, which initially operated in the Menomonee Valley at 718 Hanover. His operations were co-located with the Seamless Structural Company at the corner of Hanover and Burnham Streets.
George Westinghouse had developed an air braking system for steam locomotives and felt that Christensen's invention constituted patent infringement, suing him in December 1906. Westinghouse Air Brake Company acquired National Electric, renaming the company the National Brake & Electric Company, which refused to pay royalties to Niels Christensen. Christensen promptly countersued, starting a 24-year legal battle that went before the US Supreme Court on three separate occasions over the rights to manufacture compressed air brake systems for streetcars.
In 1933, working in his basement, Christensen discovered by trial and error that a ring-shaped piece of rubber in a groove one and a half times long as the minor radius of the ring made a reliable, tight seal of a piston sliding in a cylinder. He applied for a U.S. patent in 1937 and it was granted two years later.[2]
After Pearl Harbor, the United States government bought the rights to many war-related patents, and made them available to manufacturers royalty-free. Christensen was paid $75,000. When the war ended (formally in 1952) and the patent rights were transferred back to him, the patent had only four years left. Litigation resulted in a $100,000 payment to his heirs in 1971, 19 years after his death.[3][4][5]
Selected listing of inventionsedit
Propeller (1369399) – filed October 6, 1916; issued February 22, 1921
Power controller for vehicle brakes (2150022) – filed November 3, 1932; issued March 7, 1939
Air compressor (2074980) – filed October 17, 1932; issued March 23, 1937
Brake mechanism (2197068) – filed March 10, 1938; issued April 16, 1940
Automobile wheel and brake mechanism (2172788) – filed July 16, 1935; issued September 12, 1939
Referencesedit
^No. 555:O-Ring (John H. Lienhard, University of Houston)
^O-Rings: A Public Radio Commentary by Bill Hammack (William S. Hammack Enterprises) [1]
^O-Ring History (Ge Mao Rubber Industrial Co., Ltd.)
^Ring Master (George Wise, "Invention and Technology Magazine" Spring/Summer 1991, Volume 7, Issue. American Heritage Publishing . Archived from the original on 2007-02-23. Retrieved 2006-09-07.
^339 F2d 665 Jo. C. Calhoun, Jr., and Esther C. Young, Executors of the Estate of Niels A. Christensen (Deceased) v. United States (OpenJurist.org) [2]
Related readingedit
Weber, Robert John and David N. Perkins Inventive minds: creativity in technology (Volume 49. Oxford University Press. 1992)
Christensen, Niels A. U. S. Patent 2,180,795 (Packing. November 21, 1939)
External linksedit
Portrait of Niels A. Christensen
January 01, 1970
niels, christensen, danish, sport, shooter, niels, christian, christensen, other, people, named, nils, christensen, nils, christensen, disambiguation, niels, anton, christensen, august, 1865, october, 1952, danish, american, inventor, whose, principal, inventi. For the Danish sport shooter see Niels Christian Christensen For other people named Nils Christensen see Nils Christensen disambiguation Niels Anton Christensen 16 August 1865 5 October 1952 was a Danish American inventor whose principal invention was the O ring the ubiquitous hydraulic seal Niels Anton ChristensenPersonal detailsBorn 1865 08 16 16 August 1865DenmarkDied5 October 1952 1952 10 05 aged 87 ProfessionEngineer and Inventor Contents 1 Early years 2 Work 3 Selected listing of inventions 4 References 5 Related reading 6 External linksEarly years editNiels Anton Christensen was born on a farm in Torring Uldum Municipality Denmark He showed an early aptitude for mechanics and apprenticed to a machinist in Vejle Denmark After completing his apprenticeship he entered the Technical Institute of Copenhagen now the University of Copenhagen Faculty of Science In 1891 Christensen immigrated to the United States when he was 26 years old 1 Work editChristensen became a leading draftsman at Fraser and Chalmers in Chicago a manufacturer of machinery for industry mining and transportation While working in Chicago he witnessed an accident of a new electric railway which resulted in two deaths and a number of injuries because the conductor was unable to stop the rail cars in time using the mechanical brake Christensen decided to design and build a power brake The Christensen air brake was successfully tested on Detroit s streetcar system but a downturn colloquialism of the economy prevented Christensen from manufacturing and marketing the system He worked briefly on electrical systems for Chicago s Columbian Exposition and then was hired by the E P Allis Company of Milwaukee While at E P Allis he continued to develop his air brake for electric rail cars and streetcars In 1896 he obtained financial backing that allowed him to make an experimental test apparatus He also secured patents on the new valve mechanism In early 1897 he founded Christensen Engineering Company which initially operated in the Menomonee Valley at 718 Hanover His operations were co located with the Seamless Structural Company at the corner of Hanover and Burnham Streets George Westinghouse had developed an air braking system for steam locomotives and felt that Christensen s invention constituted patent infringement suing him in December 1906 Westinghouse Air Brake Company acquired National Electric renaming the company the National Brake amp Electric Company which refused to pay royalties to Niels Christensen Christensen promptly countersued starting a 24 year legal battle that went before the US Supreme Court on three separate occasions over the rights to manufacture compressed air brake systems for streetcars In 1933 working in his basement Christensen discovered by trial and error that a ring shaped piece of rubber in a groove one and a half times long as the minor radius of the ring made a reliable tight seal of a piston sliding in a cylinder He applied for a U S patent in 1937 and it was granted two years later 2 After Pearl Harbor the United States government bought the rights to many war related patents and made them available to manufacturers royalty free Christensen was paid 75 000 When the war ended formally in 1952 and the patent rights were transferred back to him the patent had only four years left Litigation resulted in a 100 000 payment to his heirs in 1971 19 years after his death 3 4 5 Selected listing of inventions editPropeller 1369399 filed October 6 1916 issued February 22 1921 Power controller for vehicle brakes 2150022 filed November 3 1932 issued March 7 1939 Air compressor 2074980 filed October 17 1932 issued March 23 1937 Brake mechanism 2197068 filed March 10 1938 issued April 16 1940 Automobile wheel and brake mechanism 2172788 filed July 16 1935 issued September 12 1939References edit No 555 O Ring John H Lienhard University of Houston O Rings A Public Radio Commentary by Bill Hammack William S Hammack Enterprises 1 O Ring History Ge Mao Rubber Industrial Co Ltd Ring Master George Wise Invention and Technology Magazine Spring Summer 1991 Volume 7 Issue American Heritage Publishing AmericanHeritage com RING MASTER Archived from the original on 2007 02 23 Retrieved 2006 09 07 339 F2d 665 Jo C Calhoun Jr and Esther C Young Executors of the Estate of Niels A Christensen Deceased v United States OpenJurist org 2 Related reading editWeber Robert John and David N Perkins Inventive minds creativity in technology Volume 49 Oxford University Press 1992 Christensen Niels A U S Patent 2 180 795 Packing November 21 1939 External links editPortrait of Niels A Christensen Retrieved from https en wikipedia org w index php title Niels Christensen amp oldid 1149988502, wikipedia, wiki, book, books, library,
