Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 142,846 pages of information and 228,791 images on early companies, their products and the people who designed and built them.
Lucien Charles Hippolyte Juy was a French industrialist who made derailleur gears. 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.