While looking for something else, I think I found the maker of your vise. The front jaw is a different shape, but there's enough in common that it's probably from the same company. It was made under contract for the Ware Twin Engine Truck Company of Minneapolis. The hard part was figuring out what forum I had seen your vise on.
Here's a couple links with info:
http://tinyurl.com/km2nqc3
http://tinyurl.com/mgs4kqo
http://tinyurl.com/lby23fn