Crank for skylight window

I will do my best to help. Yours looks pretty old, though, so we may not be able to get you an exact match. I'm reminded of our chain driven 39-379 skylight operator, but I'm not sure if you can adapt it to your window. The casing and dimensions are not the same as yours, so if it can work it would require some measure of alteration to where it installs. Take a look and see what you think.