[GreenKeys] Model 14 Typing Reperforator

[Duncan M. Brown]

Jim,

Thanks for your comments.

Tom Tilson sent me a picture of one of his units that printed over the feed
holes:

"If you would like a can full of chad from my M28 typing reperf, I will
gladly send you some....
  It prints in between the feed holes--small, but readable."


About the Kleinschmidt tape units - they also typed 6 characters after the
punch.  They print on the "bottom" of the tape (edge closest to the
operator) and the type wheel has to slide across the tape, so it can't type
in the area of the punches. 

I hadn't heard of "lightning chad" before.  Sounds like their electronics
were very susceptible to EMI.  Good they didn't try RTTY!

have fun,

Duncan



> [Original Message]
> From: Jim Haynes <jhhaynes at earthlink.net>
> To: Duncan M. Brown <duncanancy at earthlink.net>
> Cc: <greenkeys at mailman.qth.net>
> Date: 20-Apr-09 23:14:54
> Subject: Re: [GreenKeys] Model 14 Typing Reperforator
>
> I can't say with authority why Teletype made them both ways - of
> course as you note the chadless style provides a surface to type on,
> and also avoids the chad collection problem.  After that notable
> election fiasco we could say that chadless tape is all hanging chads.
>
> You probably know that in M35 there were some typing perfs and reperfs
> that typed between the feed holes.
>
> I don't know if there was a problem with reading chadless tape -
> certainly there would be with something like a photo reader, but
> Teletype didn't use those.  Maybe another consideration is that
> fully perforated tape will spool up tighter than chadless, so you
> have to empty the used-tape reel less often.
>
> Note that the Teletype typing reperfs type 6 characters away from
> the holes representing the character.  The Kleinschmidt design
> that types on the edge can type the character right in line with
> the holes.  Western Union also had some printer-perforators that
> typed on the edge of wide tape.
>
> Someone at Teletype did some unsuccessful experiments with a reusable
> tape - made of mylar and pre-punched like chadless tape with all holes
> punched.  Then the "punch" would just push the lids up, and after going
> through the reader they would be pushed back down again.  But after a
> few passes they either break off or fail to stay down, so you get
> errors.
>
> There are lots of strange patents for reusable or cyclic storage
> devices.  Such as a loop of metal tape with holes punched and hinged
> lids that can be swung to cover the holes, pushed aside to open them,
> read by a more or less ordinary reader, and then reset to the closed
> position.  There are a number of designs based on strings of balls
> of different sizes.  And there was one in the form of a wheel or drum
> having columns of 5 pins that could be pushed inward or outward.
> A writing station pushed the pins and a separate reading arm sensed
> them and could rotate around the drum independent of the writing
> station.  Western Union actually used those devices.  When using a
> multiplex system they allowed the keyboard operator or a start-stop
> line to write to the drum at random speed and the multiplex to read
> from it at the synchronous speed required (and of course to put in
> blanks if reading caught up to the writing).
>
> At some early RTTY gatherings (and I don't know if this was a practice
> adopted from the wire telegraph business) someone would be "honored"
> by being presented with an award consisting of a thimbleful of chads.
>
> Teletype's high-speed product line always fully perforated the tape,
> since there was no typing reperforator working at that speed.  My
> former boss told me about a high speed tape-to-tape project they
> were working on, and were having trouble with excessive errors in
> testing.  They worked very hard and were in danger of missing the
> product deadline but couldn't find the cause of the errors.
> Eventually someone discovered that the chads were falling into a
> painted metal chad container, and were picking up an electrostatic
> charge in the process.  When the charge got high enough there would
> be a tiny arc through the paint to the framework and the electronics
> would make an error.  So the solution was to remove the paint and
> make a positive ground connection between the chad bucket and the
> frame.  No more errors.
>
>
>
>
> jhhaynes at earthlink dot net