Encyclopedia Of Detroit

Copeman, Lloyd Groff

Lloyd Groff Copeman was an inventor who contributed significantly to contemporary technologies. He was born on December 29, 1881 and raised east of Flint, Michigan in Hadley Township. He studied engineering in East Lansing at the college now known as Michigan State University. Copeman continued to educate himself by working at electric utilities in Philadelphia, Pennsylvania, Spokane, Washington and locally at Detroit Edison and Consumers Power.

In 1909, Copeman patented an electric thermostat, leading to the functionality of the electric stove. Subsequently he founded Copeman Electric Stove Company in 1912 in Flint, backed by J. Dallas Dort, partner of automobile pioneer William Durant. In 1913, thanks to a suggestion by his wife Hazel, Copeman created a toaster with an automatic bread turner, which was also produced by his company. In 1917, he sold Copeman Electric Stove to the Westinghouse Electric Corporation in Mansfield, Ohio. 

Sponsored by his friend Dort, Copeman joined the Detroit Athletic Club and became acquainted with Henry Ford, the Fisher and Dodge brothers, and met Thomas Edison, along with fellow Flint residents Charles Mott, and William Durant.  

Copeman wanted to create more user-friendly technologies. In 1918, he, along with stove company investor and onetime Flint mayor Edwin Wood Atwood, established the Copeman Laboratories Company in Flint, which allowed him to dedicate his time to inventing. The business was located above the old Durant-Dort Carriage Company.

In 1928, Copeman turned an incident of removing frozen slush from a rubber boot into his idea for a rubber ice cube tray. This became his most successful and popular invention, earning him one million dollars in royalties. Another successful invention, still sold today, is the Flexor-Line clothesline made of braided rubber surgical tubing.

Copeman moved back to the family homestead south of Lapeer, bought more land, and created an estate he called Kinnikinic, still owned by the family. There, he lived the life of a gentleman farmer. Copeman died on July 5, 1956 after spending his life dedicated to inventing. He is buried at Oakwood–Mount Pleasant Cemetery.