Japanese Patent # S58-67587 - SunTour

Japanese Patent S58-067587  - SunTour main image

This SunTour patent from 1981 describes a set of parallelogram-free derailleur designs that use a continuous loop of wire, toothed band or even roller chain to keep the pulley cage aligned to the chainline. SunTour never used these systems on a production model. But, 30 years later, both Tiso and FSA created prototypes that used a tooth belt in almost exactly the way described here.

  • Publisher: Japan Patent Office
  • Inventor: Nobuo Ozaki
  • Country: Japan
  • Date: Priority date October 1981
  • Derailleur brands: SunTour with inspiration for Tiso and FSA
  • Derailleurs: none - but is curiously simliar to the Tiso electronic derailleur