French Patent # 763,536 - Rivierre

French Patent 763,536 - Rivierre main image

This 1933 patent, with its childish drawings of a single pulley rear derailleur, may, just possibly, be the earliest manifestation of a parallelogram design.

The drawings do not look like the work of an engineer, and it is not clear if the design was ever produced. The inventor is Gaston Rivierre, a distinguished cyclist both as a professional and a 'vet', who was known to have a keen interest in derailleurs, and, indeed, in many aspects of bicycle technology.