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Lloyd Groff Copeman

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Name  Lloyd Copeman
Education  Michigan State University
Role  Inventor
Lloyd Groff Copeman wwwlloydcopemancomimagessitehomelloydsmalljpg
Died  July 5, 1956, Michigan, United States

Lloyd Groff Copeman (28 December 1881 – 5 July 1956) was a prolific American inventor who devised the first electric stove and the flexible rubber ice cube tray, among other products. Copeman was raised by his Canadian parents on a farm in Hadley Township, Michigan which was later incorporated into Farmer's Creek, Michigan - located approximately 20 miles east of Flint, Michigan. He studied engineering at the former Michigan Agricultural College, now Michigan State University in East Lansing, Michigan.



Although he is not extremely well known today, Lloyd Groff Copeman developed many inventions and ideas that benefited many people. He has nearly seven hundred patents in his name. He once told his grandson that he could walk into any store and find one of his inventions.

His first successful patented inventions, patented in 1909, were an electrothermostatic heat regulator for more effective control of stove and toaster heating elements and a thermostat for high-tension power cables.

Before this, while working for the Washington Electric Company in 1906, Copeman developed a design for an electric version of the gas stoves which had been available in Britain and the USA for several decades. Development of the idea took several years, but in 1912 the Copeman Electric Stove Company was formed in the city of Flint, Michigan to produce the Copeman Electric Stove (also marketed as the "fireless cooker"). Westinghouse Electric Corporation bought the company in 1917, moved production to Mansfield, Ohio, and continued to develop and improve the stove.

From 1913, another of Copeman's inventions, a toaster with automatic bread turner, was also produced by the Copeman Electric Stove Company. Electric toasters were a recent invention at that time - the first commercially successful version was patented in July 1909 - and the bread had to be turned manually once the first side had been toasted. During a shopping trip, Copeman's wife Hazel gave them the idea for a toaster which turned the bread without manual intervention, and in 1914 a patent for what Copeman called the Automatic Toaster was filed in Hazel's name. Five other toaster-related patents were granted to both Lloyd and Hazel during the same year. The invention of the pop-up toaster in 1926 superseded Copeman's innovations, however.

A company called Copeman Laboratories Company had been established in Flint, Michigan during the year 1918 to allow Copeman to dedicate his time to inventing, although he also spent a lot of time at his farm in Farmer's Creek, where he would lock himself in the basement - sometimes for up to a week, with his wife bringing him meals on a tray - and develop new ideas and products. Examples of his work at this time, which met with varying success, included injecting chickens with solutions to make their meat taste like beef; pioneering experiments in the development of latex; the Copeman Lubri-Cap, grease-filled paper cups for lubricating wheel bearings (the patent for this product was bought for $178,000 by the Alemite Manufacturing Corporation, the same corporation that also owned the patent rights to the Zerk fitting); Flexoline clothes lines, which are still manufactured today; a device to use dry ice to cool bottles of beer; self-extinguishing cigarettes; and a rust-reducing latex coating for motor vehicles.

Copeman's most successful and remunerative invention, however, was the rubber ice cube tray. One day in 1928, while walking through some woods collecting sap for maple syrup, he noticed that slush and ice flaked off his rubber boots easily, rather than adhering to them. Having recalled this incident over lunch with his patent attorney, he conducted experiments using rubber cups, and later set about designing and then patenting different types of tray: a metal tray with rubber separators, a metal tray with individual rubber cups, and a tray made completely of rubber. Sales from this invention earned Copeman approximately $500,000, equivalent to $10 million today.

Personal life

Copeman was born in Hadley, Michigan, the son of Caroline Estelle (nee Groff) and John Wesley Copeman. He married Hazel Dawn Berger, in 1904, and they had three children: Lloyd Berger Copeman (1907–1968), Ruth Mary Copeman Ronstadt (1914–1982), and Elizabeth Jane Copeman Gerlach (1918–1998).

His granddaughter, Linda Ronstadt, is a legendary recording artist - who has been awarded a record 10 Grammy Awards to date - as well as one of the biggest-selling female singers of all time. Linda's mother was Ruth Mary Copeman Ronstadt, Lloyd's daughter.



Electrical heating unit. No. 1,138,733; May 11

Electromagnetic switch. No. 1,141,174; June 1

Electric stove. No. 1,141,175; June 1

Electrically heated oven. No. 1,141,176; June 1


Automatically controlled electrical cooking apparatus. No. 1,180,571; April 25

Collapsible grease-capsule. No. 1,190,382; July 11


Grease-cup. No. 1,222,185; April 10


Grease-cup. No. 1,269,159; June 11

Grease-cup. No. 1,287,889; June 11

Drill. No. 1,264370; April 30

Grease-cup. No. 1,287,889; December 17


Grease-cup. No. 1,294,773; February 18

Grease-cup. No. 1,300,699; April 15

Adjustable thermometer. No. 1,312,834

Grease-cup. No. 1,292,594

Grease-cup. No. 1,314,073; August 26

Shank and handle. No. 1,314,078; August 26



Heating apparatus. No. 1,336,552; April 13

Adjustable thermostat. No. 1,349,364

Toaster. No. 1,356,042; October 19

Tool holder. No. 1,361,021; December 7


Refrigeration apparatus. No. 1,396,996

Grease-cup. No. 1,368,546; February 15

Grease-cup. No. 1,395,336; November 1


Refrigerating apparatus. No. 1,409,283; March 14

Refrigerating apparatus. No. 1,415,992; May 16

Refrigerating apparatus. No. 1,430,153; September 26

Refrigerating apparatus. No. 1,430,154; September 26


Refrigerating apparatus. No. 163,419; July 31

Refrigerating apparatus. No. 1,472,266; October 30

Refrigerating apparatus. No. 1,472,267; October 30

Refrigerator. No. 1,444,589; February 6


Refrigerator latch. Re. 15,908; September 2

Refrigerator latch. No. 1,489,918; April 8

Refrigerator door construction. No. 1,503,486; August 5

Refrigerator lining. No. 1,509,932; September 30

Casting and plastic materials. No. 1,515,150; November 11

Casting stone. No. 1,518,254; December 9

Water control for refrigerating system. No. 1,519,757; December 16

Refrigerating apparatus. No. 1,517,534; December 2


Refrigerating apparatus. No. 1,526,964; February 17

Wall construction. No. 1,526,965; February 17

Molding the shells of refrigerators. No. 1,538,467; May 19

Casting refrigerator doors. No. 1,538,467; May 19

Refrigerator. No. 1,538,469; May 19

Collapsible molding dies. No. 1,538,471; May 19

Refrigerator construction. No. 1,542,862; June 23

Refrigerator. No. 1,548,825; August 11

Bushing construction. No. 1,564,947; December 8

Refrigerator doors. No. 1,564,948; December 8


Refrigerator manufacture. No. 1,570,617; January 26

Refrigerator construction. No. 1,574,868; March 2

Refrigerator. No. 1,603,905; October 19

Refrigerator apparatus. No. 1,585,016; May 18


Refrigerator construction. No. 1,644,981; October 11

Drinking water supply for refrigerators. No. 1,618,514; February 22

Water cooler. No. 1,633,372; June 21

Match-plate pattern. No. 1,644,968; October 4

Refrigerator. No. 1,644,983; October 11

Refrigerator. No. 1,644,984; October 11

Refrigerator manufacture. No. 1,644,985; October 11

Refrigerator construction. No. 1,644,986; October 11

Refrigerator. No. 1,644,987; October 11

Cabinet construction and building the same. No. 1,644,988; October 11


Sharp freezing container for mechanical refrigerators. No. 1,675,599; July 3

Refrigerator cabinet and controlling the temperature therein. No. 1,618,398; August 21

Table top construction. No. 1,656,422; January 17

Method and apparatus for accelerating setting of stone castings. No. 1,656,423; January 17

Making match plate patterns. No. 1667,720; May 1

Stone mold. No. 1,667,721; May 1

Match plate pattern. No. 1,667722; May 1

Table top construction. No. 1,667,723; May 1

Container for power refrigeration. No. 1,671,761; May 29

Cooling unit for refrigeration apparatus. No. 1,671,762; May 29

Refrigerating cabinet and controlling and operating the same. No. 1,681,399; August 21

Refrigerator or cabinet. No. 1,692,159; November 20


Balloon construction. No. 1,714,097; May 21

Sharp freezing container for mechanical refrigerators. Re. 17,278; April 23, Re. 17,279; April 23

Table top construction. No. 1,700,155; January 29

Making stone castings. No. 1,700,156; January 29

Table. No. 1,701,529; February 12

Refrigerating device. No. 1,703,299; February 26

Artificial stone refrigerator and forming the same. No. 1,703,511; February 26

Refrigerator cabinet. No. 1,710,405; April 23

Refrigerating apparatus. No. 1,710,406; April 23

Method and apparatus for forming and maintaining sanitation in ice cream cabinets or the like.

No. 1,711,721; May 7

Storage compartments for ice cream cabinets or the like. No. 1,711,722; May 7

Flexible sharp freezing container. No. 1,740,919; December 24


1939 Refrigerating unit. No. 1,744,038; January 21

Method of refrigerator manufacture. No. 1,757,450; May 6

Water cooler. No. 1,771,433; July 29

Sharp freezing container. No. 1,777,483; October 7

Refrigerator cabinet. No. 1,777,786; October 7

Refrigerator. No. 1,777,787; October 7

Refrigerating unit of fired ceramic material. No. 1,781,778; November 18

Method and apparatus for positioning and sealing ice cram cans in ice cream cabinets.

No. 1,786,827; December 30


Ice cream cabinet. No. 1,789.587; January 20

Sharp freezing container for ice cream cabinets. No. 1,807,587; June 2

Dispensing unit embodying mechanical refrigerator. No. 1,811,456; June 23

Sharp freezing unit. No. 1,816,211; July 28

Refrigerating unit. No. 1,816,638; July 28

Sharp freezing container. No.1,817,544; August 4

Sharp freezing container. No.1,817,545; August 4

Refrigerating apparatus and heat transfer therein. No. 1,818,673; August 11

Unit formed partially of fired ceramic material. No. 1,822,013; September 8

Apparatus for controlling the temperature of unit containers. No 1,824,535; September 22


Sharp freezing unit. No. 1,839,651; January 5

Refrigerating system. No. 1,840,619; January 12

Refrigerating system. No. 1,840,702; January 12

Cooling chamber for mechanical refrigerating unit. No. 1,872,685; August 23

Method and apparatus for freezing liquids. No. 1,878,685; August 23

Flexible sharp freezing container. No. 1,879,602; September 27

Refrigerating unit. No. 1,879,922; September 27

Sharp freezing structure. No. 1,882,209; October 11

Method and apparatus for refrigerating. No. 1,887,580; November 15


Refrigerating apparatus. No. 1,902,016; March 21

Cooling unit. No. 1,912,826; June 6

Cooling unit construction. No. 1,912,827; June 6

Mold construction for reproduction of patterns in rubber. No. 1,913,747; June 13

Clothespin. No. 1,916,556; July 4

Closure member and forming and applying. No. 1,916,857; July 4


Refrigerating system. Re. 19,055; January 16

Storage and dispensing unit for frozen foods. No. 1,952,422; March 27

Treating fruit or other growing vegetable matter. No. 1,955,950; April 24

Waterproof and puncture-proof paper. No. 1,976,329; October 9


Refrigerator structure. No. 2,002,339; May 21

Method and apparatus for cooling beer. No. 2,010,060; August 6

Protective coatings and applying and removing. No. 2,020,256; November 5


No patents


Protective coating and applying and removing. No. 2,082,791; June 8

Bucket and bucket protector. No. 2,071,112; February 16

Dispensing device for sheet rubber deposited from an aqueous dispersion of rubber and forming the same. No. 2,075,178; March 30

Device for making and storing ice. No. 2,088,840; August 3

Method and apparatus for conditioning and dispensing beer. No. 2,075,088; October 19


Concrete or cement structure. No. 2,112,452; March 29

Apparatus for handling ice cubes. No. 2,113,014; April 5

Refrigerating structure. No. 2,114,996; April 26

Protecting and forming pre-finished metal. No. 2,120,461; June 14

Protective coating and process of applying and removing. No. 2,132,230; June 14

Package structure. No. 2,134,908; November 1


Bird shelter. No. 2,151,010; March 21

Mounting bracket. No. 2,184,633; December 26

Dispensing device for sheet rubber deposited from an aqueous dispersion of rubber and forming and using same. Re. 21,065; May 2

Protective coating and applying and removing. No. 2,169,225; August 15

Coating knit articles and products thereof. No. 2,172,251; September 5

Portable beverage conditioning and dispending apparatus. No. 2,182,116; December 5

Coating knit articles and products thereof. Re. 21,269; November 21


1940 Bird feeding station. No. 2,216,511; October 1

Birdhouse. No. 2,219,297; October 29

Cigarette and treating the same. No. 2,185,293; January 2


Suet Cake container. No. 2,235,959; March 25

Flour sifter combination. No. 2,252,701; August 19

Container for confections. No. 2,248,963; July 15


Collapsible birdhouse. No. 2,292,614; August 11

Birdhouse construction. No. 2,295,891; September 15

Treating textile fabrics and the products thereof. No. 2,281,830; May 5


Clothesline. No. 2,318,275; May 4

Dispensing and using rubber. No. 2,307020; January 5

Closure member and applying same. No. 2,356,825; August 29


No patents listed


No patents listed


No patents listed


No patents listed


Cream separator. No. 2,477,863; August 2

Apparatus for dispensing ice cubes. No. 2,484,017; October 11



Ice tray. No. 2,514,476; July 11

Hand tool for agriculture implements. No. 2,528,947; November 7


Method and apparatus for the manufacture of cigarettes. No. 2,543,277; February 27


Spill guard for ice tray. No. 2,593,106; April 15


Tractor hitch. No. 2,627,423; February 2

Bottle closure. No. 2,634,012; April 7


2,688,236; Cl. 62-108.5

(Kisselle-ice tray grid) 2,671,321; March 9


2,712,666; Cl. 15-142

2,704,732; Cl. 117-155


Copeman, Lloyd Groff deceased; Elizabeth Jane (Betty), Gerlach, executrix Portable beverage conditioning and dispensing apparatus. No. 2,749,719; June 12

Cl. 62-91.5


Moisture impervious container. No. 2,781,159; February 12

Cl. 229-16


Lloyd Groff Copeman Wikipedia

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