This Japanese Patent describes an early prototype of the Maruishi PC system. This was a 1970s electro-mechanical device that takes an electrical signal from the special gear lever and then interprets it to pull the appropriate amount of bowden cable to move the rear derailleur to the correct position.

Electric shifting from a long-lost time when men really did walk on the moon - what could be cooler than that?

This patent has a priority date of 1974. This is different from US Patent # 4,065,983, which has slightly different images and a later priority date of 1976.

• Publisher: Japan Patent Office
• Inventor: Yasuo Mimura
• Country: Japan
• Date: Priority date September 1974
• Derailleur brands: Maruishi
• Derailleurs: Maruishi PC electro-mechanical system