Can you help solve a mystery?

Hi all!

Hoping to help a local antique dealer solve a mystery! In his own words -

**"Several years ago I came across this tool in an old antique store.  The proprietor didn't know what it is either.  I'm sort of a toolhead so I had to buy it.**

**I have asked around numerous times, but the best guess I have heard is that it is some kind of tool used in Cooperage (Barrel Making).**

**The tool is about 3 feet long.  The "front" end (3rd photo) has clamps for some kind of circular rim, and carries an articulated swiveling and sliding base for the handle.  The handle has a mounting bracket (4th photo) with setscrew for some kind of tool with an approx.  1" shaft.  The handle can go back and forth in a circle, and also up and down.  The shaft of the tool stays vertical throughout these motions. This might make a great item for stirring a vat of wine, but I doubt that is what it is.  Hope you can help!"**

Any thoughts as to what it could be? Thanks in advance for your help!

Edit to add photos!