Old "YOKE" pliers for joining leather or canvas flat drive belts... the type used to drive early industrial machinery driven by steam engines etc., and lots of farm equipment until well after World War Two.
You'll even see the flat belt drive pulleys on many of the old John Deere and Farmall tractors. These flat belt drives used to run everything from corn shellers to cream separators.
These pliers were made by the BF Machine Co - Boston, Mass. They have a patina of age and wear, but are very usable