Originally Posted by
ThermionicScott
Frank Berto describes the Bilis as an "another expanding chainwheel" page 128 of "The Dancing Chain." The picture looks like yours, Catnap.
I wonder if there was supposed to be a cable that attached to something via an inner-side hole to select the gear.
Expanding, eh? In that case it sounds like it might be of the Citroen 2CV centrifugal clutch type - a drum within a drum with weighted metal strips, made of a springy steel, around the outer circumference of the inner drum, attached at only one end of the strip so that at the revs increase the unattached ends of the strips move out and make contact with the outer drum and turn it.