Lucien Juy
Encyclopedia
Lucien Charles Hippolyte Juy was a French industrialist who made derailleur gears
Derailleur gears
Derailleur gears are a variable-ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets of different sizes, and a mechanism to move the chain from one sprocket to another...

. He is credited with making the first derailleur with a collapsible parallelogram . A hinged frame swung in and out from the frame and fed the chain to one of a number of sprockets attached to the hub. Juy's derailleurs, sold as Simplex derailleurs, were novel in having a jockey wheel to correct the tension of the chain as it moved across differently sized sprockets.

History

Lucien Juy owned a bicycle shop in Dijon
Dijon
Dijon is a city in eastern France, the capital of the Côte-d'Or département and of the Burgundy region.Dijon is the historical capital of the region of Burgundy. Population : 151,576 within the city limits; 250,516 for the greater Dijon area....

, Côte d'Or, France. It was there that he made the first Simplex derailleur in 1928. The bicycle historian Hillary Stone said: "It used a single pulley to tension the chain and a pair of guide plates to push the chain to each one of two sprockets. The whole arm was spring-loaded in order to tension the chain – this was the first use of the sprung top pivot which was to become an essential part of the modern indexed derailleur as we know it today. The pulley and guide plates were moved sideways on a push-rod by means of a chain pulling through the centre of the push-rod. Lucien Juy managed to persuade the management of the Alcyon
Alcyon
The Alcyon was a French bicycle, automobile and motorcycle manufacturer between 1890 and 1957.- Origins :Alcyon originated from about 1890 when Edmond Gentil started the manufacture of bicycles in Neuilly, Seine. In 1902, this was complemented by motorcycle production and in 1906, the first cars...

 racing team to fit his Le Simplex gear to their machines for the 1928 Paris–Roubaix – unfortunately the riders revolted and refused to use the new unproven gears."

By 1933 Juy claimed he was making 40,000 derailleurs a year . The derailleur was used to win four French national championships that year. His five-speed Champion du Monde model in 1936 was the first to use a chain of 3/32 rather than 1/8-inch. Antonin Magne
Antonin Magne
Antonin Magne was a French cyclist who won the Tour de France in 1931 and 1934. He raced as a professional from 1927 to 1939 and then became a team manager...

, after whose title it was named, use the gear to win the world championship in 1936.

In 1962 Juy broke with tradition and made his front and rear derailleurs with nylon frames. A historian of bicycle derailleurs, Michael Sweatman, says: "He did not do things by halves - instead of dipping in a toe and using the odd plastic part - he jumped in up to his neck and made the entire parallelogram - both knuckles and both parallelogram plates - out of polyoxymethylene
Polyoxymethylene
Polyoxymethylene , also known as acetal, polyacetal, and polyformaldehyde, is an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability....

(which Du Pont branded as 'Delrin'). It was a bold, dynamic, modern and, ultimately, disastrous move."
Production of all Simplex gears ended in the 1990s. A street in Dijon is named in Juy's memory.

Juy was issued 26 United States patents from 1950 to 1980, mostly for bicycle components.
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