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Thermo King Model C

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Black and white photograph of Frederick McKinley Jones standing next to a truck outfitted with a mobile refrigeration unit, c.1950.

Frederick McKinley Jones standing next to a truck outfitted with a mobile refrigeration unit, c.1950.

In 1939, Frederick McKinley Jones patented the world’s first successful refrigerated transportation system. At the time, he was working for the Minneapolis-based company U.S. Thermo Control. Two years later, he released an improved version, the Model C, which revolutionized the agriculture and military industries.

Frederick McKinley Jones patented more than sixty inventions over his sixty-seven-year lifetime, making him one of the most prolific African-American inventors ever. The Thermo King Model C stands as his most prominent achievement.

While living in Hallock in the 1920s, Jones built a transmitter for the town’s radio station. Joe Numero, an entrepreneur from Minneapolis, noticed the station’s excellent quality and offered Jones a job at his sound system company.

Jones accepted and moved to the Twin Cities in the early 1930s. Though the company thrived thanks to Jones’s engineering prowess, Numero sold it to RCA so that he could start a joint venture with the young inventor.

In 1938, Numero founded a new venture: the U.S. Thermo Control Company. Jones served as vice president of engineering. One year later, Jones filed for Thermo Control’s first patent: the Model A, the world’s first successful system for refrigerated transportation.

Until the 1940s, transported goods were cooled by salt and ice. This created temperature inconsistencies and required manual labor. Model As were designed to be mounted onto the undersides of semi-trucks and to pass refrigerant tubing to their trailers. In the words of Jones’s patent, these tubes “condition[ed] the air” within the compartment by “tempering, humidifying and circulating.”

The Model A worked, but it was heavy and bulky. The Model B, though more compact, was not ready for intensive use. In late 1941, Jones unveiled the Model C.

Jones’ Model C was the first cooling unit mounted on the front side of a vehicle. Units fixed in this location collected less dirt than under-mounted versions. More important, the Model C’s unitary, metal body gave it the rigidity to withstand long trips and the lightness—seven hundred pounds—to save precious engine power. Running the unit were a Briggs and Stratton single cylinder engine, a Lynch Model Par S-2150 reciprocating compressor, and a six-volt starter.

The Model C was such a revolutionary invention that Thermo Control renamed itself “Thermo King” in 1941. During World War II, Thermo King made Model Cs exclusively for the U.S. military. The military applied the invention to boats, planes, and trucks in order to transport temperature-sensitive drugs and blood plasma to soldiers in need.

The Model C became commercially available after World War II and immediately made an impact on the agricultural industry. Seasonal crops could be shipped across the world. Nations could trade perishable goods. Jones’ invention laid the groundwork for the modern supermarket.

The Model C was retired from service in the mid-1960s. By then, it had made an indelible mark on international trade. L.B. Hartz Wholesale of Minnesota purchased the original Model C and donated it to the Thermo King dealership in St. Paul. Soon afterwards, the model was put on display at Thermo King’s headquarters in Minneapolis.

As of 2015, more than three quarters of the food transported in the United States ships with a refrigeration unit. The Model C has also allowed for the shipment of a variety of goods, including photographic film chemicals, flowers, and paintings.

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Jones, F. M. “United States Patent RE23000 E: Removal cooling unit.” May 11, 1948.
https://www.google.com/patents/USRE23000

Jones, Frederick M., and Joseph A. Numero. “United States Patent 2303857: Air conditioner for vehicles.” December 1, 1942.
http://www.google.com/patents/US2303857

Ott, Virginia, and Gloria Swanson. Man With a Million Ideas: Fred Jones, Genius/Inventor. Minneapolis: Lerner Publishing Group, 1977.

“Thermo King Model C Transport Refrigeration Unit.” American Society of Mechanical Engineers, 1996.
https://www.asme.org/getmedia/565fee1c-1fa3-49e0-96f4-d5ebc1b499e1/192-Thermo-King-Refrigeration-Unit.aspx

Thermo King. Our History.
http://www.thermoking.com/global/en/our-history.html

Related Images

Black and white photograph of Frederick McKinley Jones standing next to a truck outfitted with a mobile refrigeration unit, c.1950.
Black and white photograph of Frederick McKinley Jones standing next to a truck outfitted with a mobile refrigeration unit, c.1950.
Black and white dagram of the Thermo King Model A included in Frederick M. Jones’ 1939 patent application to the U.S. Patent and Trademark Office.
Black and white dagram of the Thermo King Model A included in Frederick M. Jones’ 1939 patent application to the U.S. Patent and Trademark Office.
Black and white photograph of Frederick McKinley Jones and drafting team, c.1960.
Black and white photograph of Frederick McKinley Jones and drafting team, c.1960.
Black and white aerial photograph of the Thermo King Corporation campus in Bloomington as it appeared, c.1960.
Black and white aerial photograph of the Thermo King Corporation campus in Bloomington as it appeared, c.1960.

Turning Point

In 1941, Frederick McKinley Jones unveils the Model C mobile refrigeration system—an improvement on earlier models A and B.

Chronology

1938

Joe Numero founds the U.S. Thermo Control Company.

1939

Jones applies for and receives a patent for the Model A. U.S. Thermo Control becomes Thermo King.

1941

Jones unveils his Model C—the first cooling unit designed to be mounted on the front side of a vehicle.

1942

Thermo King provides refrigeration units to Allied troops fighting World War II.

1948

Building on existing technology, Thermo King develops units for use in rail transport.

1956

Thermo King units are installed in passenger buses.

1991

Jones and Numero receive posthumous National Medals of Technology.

2015

More than 75 percent of the food transported in the United States is refrigerated while in transit.