The Incredible Edible Rolamite!

Figure 1: Basic Rolamite Designs

(Just click to enlarge!)

When the lever, wheel, pulley, or wedge just won't do, the rolamite will get you through! Using the many marvelous properties of thin metal bands, the rolamite is a simple mechanical device with almost zero internal friction. The basic idea is that two cylinders can be held in place between two planes with a flexible metal band and roll back and forth freely. This basic design (kind of like the rollers that let drawers slide in and out, only less complicated) can be easily modified by bending or reshaping the metal band to create springs, dampening forces, "notches" where the rollers will want to stick... or pretty much anything else you can imagine!

Figure 2: A million uses! Personally I like the thermometer design using a temperature-sensitive metal the best.

(Just click to enlarge!)

Ball bearings can be substituted in most cases, but making perfectly spherical tiny metal balls is actually a pretty hard trick so most ball bearings areneither expensive or have some friction. Plus they always need to be kept clean, lubricated, and are hard to repair.

Of course many people have never heard of the rolamite. The people who discovered it in the 1960s were very enthusiastic about it's potential (see the link below for some rave magazine reviews and predictions!), but the rolamite can be a little hard to get your mind around, and, well, most people haven't heard of it, so they don't know how much they need it! But it's a great tool to think about, and the principle has been used in recent years to build super efficient devices... and we all know how important efficiency and energy conservation is!

Over the years engineers have settled a few great ideas that get used over and over: nuts and bolts, rubber o-rings, ball bearings, cheese-in-a-can. Sometimes it feels like the basic problems are all solved and we just have to apply the standard methods. But there are always special cases: for instance in extreme vacuums or lab clean rooms you can't always use screws or nuts because they can't be undone without oil in the threads (oil evaporates in a vacuum and can cause contamination. You can't use glue, tape, plastic, rubber, ball bearings, or cheese either!). So even wise old experienced engineers have to sit down and rethink the simplest machines and devices we usually take for granted.

Anyways, as you're thinking about your wild machines, keep in mind that even the simplest little ideas can be unique and world-shattering. And if you read this far go reward yourself with some cheese from a can, or at least a tasty sandwich and a glass of milk!

For more about the rolamite, check out these links!

http://www.rexresearch.com/wilkes/1wilkes.htm
http://en.wikipedia.org/wiki/Rolamite

Over and out,

Bryan Newbold
Physics '09
MIT mentor