Here's a great link to the history and overhaul of Bendix two-speed hubs:
http://www.trfindley.com/
And to keep it on-topic, I laced one of these hubs to a 700c rim and rode it on a '70's Atala "econo" track frame a few years back. Made a nice simple commuter bike.
Dave (not riding in the rain today) Neuhaus
Fanwood, NJ, USA