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Freeman first developed a block heater around 1947, and received U.S. Patent #2487326 on 8 November 1949.
He was born in Upham, North Dakota, and attended the University of North Dakota in Grand Forks, North Dakota, where he majored in electrical engineering. He was president of Five Star Manufacturing, the company that made the original block heater, and co-founded and managed Minnkota Power Cooperative from 1940 to 1982. He died in Grand Forks.
- US patent 2487326, A. L. Freeman, "Electric Internal-Combustion Engine Head Bolt Heater", issued 1949-11-08
- "Headbolt Heaters". Dakota Datebook. Prairie Public. 16 February 2004.
- UND Center for Innovation North Dakota Entrepreneur Hall of Fame: http://www.innovators.net/innovators/public_html/about_the_center/entrepreneur_hall.html.
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