This 1933 patent covers the second Durex design - that this time could actually be operated by a lever and cable. Despite being a markedly better design than Durex's first try, I am not completely sure that it made it to market. I have never seen any photos of it. If you have any relevant evidence please let me know!

• Publisher: Deutsches Patent- und Markenamt
• Inventor: Erich Lucas
• Country: Germany
• Date: Priority date April 1933
• Derailleur brands: Durex
• Derailleurs: Durex