Perusing a swap meet on the weekend, I saw not one but two of these nicely-cast iron devices. Neither of the vendors knew what they were, and we certainly didn't either. So I bought one, took a picture of it and sent it to the Duke.
One glance and he knows what it is and how it's used, and shortly thereafter an email arrives with full instructions... Not the same manufacturer but the same tool. So, now I know- and I have no use for it, I prefer a chainsaw.