Keyboard actuator

From: Dwight Elvey <elvey_at_hal.com>
Date: Thu May 11 18:36:24 2000

"John Allain" <John.Allain_at_donnelley.infousa.com> wrote:
>
> I have to jump in since someone brought up the Selectric.
>
> Has any-one here ever dismantled a Selectric? Did once
> and though I thought knew mechanisms at the time it turns
> out I sure didn't. The central mechanism seemed like a cross
> between Dr. Nim (On Topic) and DigiComp-1.
> The key presses were relayed by an almost binary series of
> pushrods to a cascaded teeter-totter matrix.
> The damndest mechanism I've ever seen. Anybody else have
> this reaction?
> Seems like a pretty good topic so I'm chiming in with this...

Hi
 I used to work on teletypes with moving drums and type boxes.
These are alway complicate machines with decoding and encoding
bars that slide this way and that. The only type that is
really simple is the more standard rotating drum that
drives a single print hammer for each key.
 Think about making mechanical software that first
takes a single input port status and then finds the
codes to send to a couple of ports. One port describes
rotation and the other lift ( or tilt ). Now think
how you'd do this mechanically. Add the fact that
you need to do all this in sequence so that it was
completed by the time the ball hit the ribbon. It
is not a simple operation. I marvel at the fact that
anyone even thought it was possible to make it work.
 Then, I've always been fascinated by a sewing machine!
Dwight
Received on Thu May 11 2000 - 18:36:24 BST

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