Ingenious Invention: Tire Chains That Deploy with the Flip of a Switch

[http://www.youtube.com/watch?v=EwLCOqIUvsU](Video...  ...since the 70s, but I've only now heard of On-Spot tire chains . These gadgets have short lengths of steel chain...  ...ver encounters heavy snow, s/he can lower them to tire level. The spindles spin with the wheels, driving...  ...l. The spindles spin wit...

http://www.neatorama.com/2013/01/18/Ingenious-Invention-Tire-Chains-That-Deploy-with-the-Flip-of-a-Switch/