As with US patent # 3,394,604, a couple of things interest me about this patent. Firstly the drawing looks like a picture of a Shimano Archery running an 1/8” chain over a three speed block. Those meaty cogs do not look like they are expecting a 3/32” chain!

Secondly the indexing system (the real subject of the patent) is entirely contained in the lever - unlike Shimano’s Positron system and very like SIS.

• Publisher: US Patent and Trademark Office
• Inventor: Kyoji Hayashi and Takehiko Kimura, assigned to Shimano
• Country: USA
• Date: US application filed March 1966, Japanese application filed March 1965
• Derailleur brands: Shimano
• Derailleurs: Shimano Archery