ID this bike

[willbuck]

My dad bought this bike at a yard sale, it has no head badge or any ID except for this serial number on the crank (6H414275). I have never seen a bike made this way - with the break apart frame in front of the seat (2 wing nuts). Any help would be appreciated. The color is original.

 

[willbuck]

another shot

 

[willbuck]

yet another

close up of the frame, where it can be taken apart.

 

[willbuck]

From what I can tell, it is a two speed with the toggle under the seat (which I have never encountered at that location.