I am sure this is within the time line but not sure if that line has a beginning. I found this looking for something else. Look at the photos of the gearing mechanism. Notice the way the gears are thrown. Sort of looks like a variation of the belt systems of the day that powered that periods machine shops. That said, also look at the derailleur levers on the head tube. Sort of pre-dates some very similar levers of the post war era.
http://www.nostalgic.net/
Ray Homiski
Elizabeth, NJ