Please Help Me If You Know What This Is

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).

If you could tell me what it is called and how it was used, please use the contact form or email me at [email protected].
Much Obliged!

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!