Old awning window with hinged operator

I am trying to identify the manufacturer of this window. The house was built in 1960 and the awning window is of a hinged metal operator that is unfolded and then you push out the window with a bit of force. I am trying to figure out how to remove this window so that I can install new windows. There is a large piece of wood in the middle of the frame, inside and outside. The window itself is not very thick, but all the framing looks to be over the top. Thanks.