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AnonTechie [soylentnews.org] writes:

As soon as SRI explained how their new Abacus transmission worked, we were absolutely sure that it was cool enough to share. In a nutshell, here’s why: It’s the first new rotary transmission design since Harmonic Drive [harmonicdrive.net] introduced its revolutionary gear system in the 1960s*, and it might give harmonic gears a literal run for their money.

Harmonic gears are great, but they’re also super duper expensive, because they require all kinds of precision machining. Alexander Kernbaum, a senior research engineer at SRI International, has come up with an entirely new rotary transmission called the Abacus drive, and it’s a beautiful piece of clever engineering that offers all kinds of substantial advantages:

The Abacus drive (named because it has components that look like the beads of an abacus) is what’s called a pure rolling transmission: there are no parts that rub or slide against each other (like gear teeth), only parts rolling against other parts. Rubbing and sliding result in wasted energy, and in fact, conventional transmissions are typically only 50 percent efficient. Kernbaum says that Abacus has an efficiency “in the high 90s,” a massive improvement.

http://spectrum.ieee.org/automaton/robotics/robotics-hardware/sri-demonstrates-abacus-rotary-transmission [ieee.org]

[Video]: SRI Abacus Rotary Transmission [jwplatform.com]

* Harmonic Drive gears are based on an ingenious mechanism known as a strain wave gear [harmonicdrive.net], which was invented in 1955 by a prolific engineer named C. Walton Musser [waltmusser.org] (his other numerous inventions include the recoilless rifle and the ejection seat [youtube.com]).

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