Brian posted these pics of a hub he has to FB’s Flatfendering Aficionado Monthly group. It’s not something I recognize. The work looks good enough to have been a prototype hub that never made production. It may have been an auto-engaging hub? Some commenters suggested a type of limited slip hub, where when a wheel begins to slip it auto-engages.

Brian wrote, “Has anyone ever seen these locking hub contraptions? Were these produced or is it a one-off? It appears to use 3 clutch plates and the ring in the center moves down over the roller cams to apply pressure to the plates. The covers look to be welding bottle caps that have 2 access holes to pry the collar from the outside.”