Unusual "C" clamp

[toolmiser]

Have you ever seen a "c" clamp like this? The "wing" part is what has the treads, and this one kind of turns-looks like someone took a punch and tried to make it stationary. I don't think it is homemade, but don't see the purpose of the wing? Brand name is "Columbian" made in USA. Unique tools like this interest me. Thanks for your comments.

 

[BuffettFan]

Never seen one before, but I would believe that the wingnut is used to lock the clamp once it is tightened.
Just a guess.

 

[Codejack]

Or to give it a "memory" feature? Tighten it to a point, set the wingnut there, back it off, and take it to where you need that distance for some reason.

 

[jakemac]

The wing was originally at the end of the threads with a pin through it to keep it fixed to the screw. The knob was added by a previous owner. For what reason ? Don't know. Maybe the end broke off the screw.

 

[toolmiser]

The "wing" is part of the sleeve that is threaded thru the "c". It sure doesn't look like it was ever made for the end. Yes I have a bunch of clamps that use the "wing" for adjustment, but this is different.