Japanese Patent # S56-31886 - Shimano

Japanese Patent S56-031886 - Shimano main image

This is a terrifyingly basic (and intriguingly retro) design for a two-speed derailleur to be used with a coaster brake hub. It manages to combine Simplex's 1930s bell crank & sliding shaft mechanism with Simplex's 1940s upside-down pulley cage from the Tour de France - a combination that Simplex themselves never even tried. But then, why resurrect one bad idea when you can resurrect two?

Overall this patent serves as a reminder that, despite the hooplah surrounding Dura-Ace, XTR et al, Shimano has never been too proud to cater to the lower end of the market.

I don't know if this object ever made it to market - but, if it did, I suspect it was only offered on domestic Japanese bikes aimed at kid's and/or 'shoppers'.