A home owner from Chicago says:
September 18, 2015
I am looking for 2 crank handles that will open my 1913 casement windows. The hardware is manufactured by John S. Gullborg Co.
Dave from SWISCO responded:
September 22, 2015
Please look at our 39-268 operator. I think this could be the one you are looking for. I have used it myself for old windows similar to this.