I had an old scrap bike that had a band brake on it.
The brake bell that attaches to the hub, screwed onto threads on the side of the hub
think the hub was a flip flop. IE threaded on both sides for a freewheel.
Think the brake backplate with the band on it, was on the axle, with the lock nut holding it onto there
It would be slighty more hassle if a spoke broke as the brake bell and the freewheel would have to be removed.