I have decided that this patent relates to the Shimano Combi 12 firstly because it shows a derailleur on which the cable runs over a wee roller close to the outer cable stop, and secondly because it shows a hub which has a fat barrel much like the 3.3.3. three speed hub. I am not entirely sure whether Shimano made a coaster brake version of their 3.3.3. hub gear - but it seems more than possible. The gear cluster shown has only three cogs - could there have been a Combi 9?
This is the earliest US patent related to a derailleur that I have found that is in the name of Keizo Shimano himself.
Browse associated derailleurs.
Shimano Combi 12 red 1965