Selectric Typewriter conversions

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Tue Feb 4 19:28:00 2003

> Agree completely. I took one apart years ago and deep
> inside were two compound lever assemblies, which could
> sound complicated, but what they did was find a kind of
> breathtaking simplicity. The lever mechanism worked exactly
> like the way a Mobile hangs and balances several inputs to
> one output. (picture below).
> I'd like to congratulate the inventor of that one.

I have a reprint of an old (1912-ish) book on Telegraphy, and it uses a
similar linkage for a binart to 1-of-n decoder to position a typewheel
for a printing telegraph machine. So the idea is pretty old.

Mildly off-topic, but of course such a linkage works with analogue
'signals' as well. I have in front of me a camera which uses a similar
linkage with the appropriate lengths to combine the settings of the
shutter speed dial/film speed control, lens aperture ring, and maximum
aperture control so as to correctly position the reference circle for the
exposure meter. I said 'mildly off topic' because this is, IMHO, a very
simple analogue computer and it's well over 10 years old.

-tony
Received on Tue Feb 04 2003 - 19:28:00 GMT