Recently NuVinci bicycle drive-train was awarded Technology Innovation of the Year. What's so special about it? It appears to be ground-breaking, though with design inspiration drawing from no less than Leonardi DaVinci.
Here's what they say: A new way of transmitting mechanical power based on spheres instead of gears. The NuVinci continuously variable planetary (CVP) technology, an innovative new continuously variable transmission (CVT), is not only helping vehicle designers and component manufacturers improve performance, ride quality and capabilities in existing products. Hum, so this means no more dérailleur popping the chain off at inopportune times? And rather than having gearing at discrete settings it can be set to the exact desired ratio. Cool.
I'm afraid the implementation goes over my head a little. The technology relies on transferring power through rotating metal spheres. Somehow by varying the angle of interfacing with the balls it varies the gear ratio. Uhm, okay, yeah, sure, so long as it works I'll be happy.
The web site says right now they're doing this for bicycles but they hope to make the technology for bigger vehicles too.
I've collected pointers to a few reviews.