US Patent # 4,143,557 - Sanyo

US Patent 4,143,557 - Sanyo main image

This is the only US Patent that is both held by Sanyo and describe their development of the Maruishi PC system. It has a priority date of 1977, which is a year after a blizzard of related Japanese patents and utility models.

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

  • Publisher: US Patent and Trademark Office
  • Inventor: Yoshitaka Wakebe, Hirofumi Matsumoto, Hiedo Momohara, Yasuyuki Tsuchida and Kazuhiro Tomoshige
  • Country: USA
  • Date: priority date April 1977
  • Derailleur brands: Maruishi
  • Derailleurs: Maruishi PC derailleur system