Those 3-arm cranks were also made by Nervar, Solida and others and were often used on cheap French bikes. I got me one of those once for a handful of euros, which enabled me to go from this ...



... to this:



Granted, the cheap 50/38 set is nowhere near as pretty as the original 52/49, but mated with a 14-28 FW it gave me a much more useful gear range.