Everyone is familiar with normal chain and sprocket drives:
http://bulgier.net/pics/bike/Antique...ed_Russian.jpg

And most of us have seen ordinary shaft drives:
http://www.nostalgic.net/bicycle399.htm

There are also treadle drives of various kinds:
http://i9.tinypic.com/4taqys4.jpg
http://www.automag.be/IMG/jpg/Levocyclette.jpg

Some bikes connect the front and rear sprockets with an intermediate
sprocket:
http://i12.tinypic.com/49j06bk.jpg

***

But I haven't seen the following two oddball drives in Sharp's
"Bicycles & Tricycles" or the early part of Berto's "Dancing Chain."
Nor could I turn them up in a quick look through some old photo
galleries. Probably they can be found in some more obscure books.

***

For lack of a better term, I think of this first design as a sawtooth
drive.

Here's a single sawtooth drive:
http://www.google.com/patents?id=uSk...=PP1&dq=618691

And here's a pair of double sawtooth drives, both from the same unsung
genius:
http://www.google.com/patents?id=fHN...=PP1&dq=609498
http://www.google.com/patents?id=thF...=PP1&dq=610157

And another double sawtooth:
http://www.google.com/patents?id=tgx...=PA1&dq=642013

The eqquivalent of a chain guard seems like a good idea.

***

I think of this related saw-tooth design as a bottle-opener drive:
http://www.google.com/patents?id=GBB...=PP1&dq=512538

***

I'd love to find photos of such beasts, or even a modern bicycle that
uses a long row of saw-teeth.

Cheers,

Carl Fogel