Tullio Campagnolo patented his first Gran Sport design in Italy in November 1950. It featured large allen bolt heads and drilled pulley wheels. Less than 2 years later Nicholás Arregui Gallastegui was busy patenting this Zeus copy in Spain.

He seems a bit confused about how the hanger plate is supposed to attach to the drop-out.

• Publisher: Oficina Española de Patentes y Marcas
• Inventor: Nicholás Arregui Gallastegui
• Country: Spain
• Date: Spanish application filed September 1952
• Derailleur brands: Zeus
• Derailleurs: Zeus Gran Sport