gears

For years, creating the gears and sprockets needed to make a microscopic robot has required the expensive and time-consuming process of silicon etching. Carving out each individual piece with a laser has made producing more than a couple of pieces prohibitively difficult and costly.

A team at Columbia University now seems to have found a way around that problem. By laying a thin sheet of metal over a special layer of polymer, the team has created nanogears that assemble themselves, opening the possibility of much faster, cheaper, widespread production.

How do you make a bicycle that never needs lube, never leaves grease on your pants, and always delivers smooth pedaling? Simple: Ditch the chain.

For its new Soho commuter bike, Trek replaced greasy metal links with a dry belt. Unlike other attempts at such bikes, the Soho is silky smooth to pedal. And it’s the first to offer multiple speeds, using an eight-gear transmission inside the rear-wheel hub.

In 1869, French clockmaker Andr Guilmet conceived the idea of connecting gears
to the pedals of a bicycle and joining them to its rear wheel with a metal chain. The invention revolutionized the bicycle and, with it, transportation. Now researchers at Sandia National Laboratories have fabricated a tiny descendant of that early chain that saves space in microelectromechanical devices (MEMS) and which may prove far more revolutionary.