If memory serves me correctly, these were a product of the Belsaw Company, the ones who made my 12" thickness planer which I bought new around 1975. They used to have a pretty good service dept. and may be able to furnish operators manuals. Perhaps try searching online for more info.
I would jump on that in a second. Just make sure that it comes with manuals. I have bought several of these on CL for less than $ 100.00 that were incomplete. They sell for over $ 1500.00 complete.
Try here. http://www.foley-belsaw.com/ . You can buy parts and catalogs.