Old World tool - What is it?

[Fastfish]

Got this from my father inlaw's stuff. Initially it looked like a hammer/pipe wrench combo. The there are no wear marks to indicate either of these uses. The "jaws" open when the handle is unscrewed. Any ideas what it is? Thank you

 

[lbgradwell]

Initially it looked like a hammer/pipe wrench combo.

That's pretty much it (except not for pipe).

In practice, it was used for nuts and as a hammer. Sometimes referred to as a "coach wrench" or "parallel-jaw wrench"...

 

[Zeke]

I think it is a hammer/wrench like a pump wrench.

 

[pozidriv]

Cool!
Indeed, looks a bit like this.
http://en.wikipedia.org/wiki/Monkey_wrench