This patent is interesting. It covers the same design as French Patent # 723,162. In the French patent the inventor is listed as Claudius Jacquemard, the owner of the Idéal brand. However, in this, British, patent, the inventor is listed as Giovanni Perona of Torino. Perhaps Giovanni is the original inventor and sold his design to Claudius.

• Publisher: UK Intellectual Property Office
• Inventor: Giovanni Perona
• Country: UK
• Date: Priority date December 1932
• Derailleur brands: Idéal
• Derailleurs: Idéal 3-speed