A visitor to the Man Cave brought this wrench by today. His father had dug the wrench up when he was bulldozing land in New Castle County, Delaware many years ago. I was not able to identify the wrench's specific application, but I think I have seen pictures of curve-handled key wrenches before. I did break the jaw and the key loose for my visitor, using judicious strikes with 4-lb. maul and a little Liquid Wrench.
Was this wrench designed for any special purpose?