Problem of the Week

Chapter 10: Energy, Work, and Simple Machines

Problem of the Week

Microengines
Microengines are the size of a sand grain but with the power of a horse. Well, not exactly. Though these minature engines etched into silicon do produce horsepower, it is as miniscule as their size.

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Figure 1 Microtransmission driving a rack and pinion unit to deflect an out-of-plane mirror.

A transmission is a type of machine that uses a set of gears to transmit the input force of the engine to an output force on an object.

Micromachines
To increase the output force of a microengine, one needs to devise a micromachine. Researchers at Sandia National Laboratories have done just that. They have produced a miniature set of gears, a transmission of sorts, that will increase the force a microengine can deliver.

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Figure 2 Close up shot of the micromachine. The width of the picture represents 200 µm.

How it Works
Figure 2 is an up-close shot of the machine. The microengine is at the top and it will turn the little gear wheel, A. Through a series of other gears, the pinion B (small gear wheel) will turn. The pinion drives the rack C. Notice on Figure 1 that the rack will push or pull on the mirror.