KatLondon wrote:

I know I've reached the end when the paper falls off the platen.

I've noticed that happens when I have some incredibly important insight which cannot get through my fingers to the paper fast enough. Doesn't actually fall out but the final warning is the paper slips. Oops.  If I think about it I just measure the typed sheet against a blank sheet when I get near the bottom of the page.

I thought of a mechanical vertical margin that would ring a bell in analogy to the horizontal margin. I'm certain such a thing could have been designed and that if it occurred to me it must have occurred to typewriter designers, so I imagine the reason that we have never seen such a thing is that it would have been just too mechanically complex and add just too much manufacturing expense. Though it would seem in place on a machine like the Hermes ambassador which from photos I have seen is a no-holds barred monster with every value added mechanism they could think of crammed in! 

Repartee wrote:

I thought of a mechanical vertical margin... I'm certain such a thing could have been designed...

It was. Posts #6 to 8.

Repartee wrote:

Uwe wrote:

Repartee wrote:

I thought of a mechanical vertical margin... I'm certain such a thing could have been designed...

It was. Posts #6 to 8.

Well, that's one design! When I first saw the backing sheet I had some rude ideas of what the audible warning would be like - something about air trapped between layers of the sheet and suddenly expelled.

But this is not mechanically complex enough for my taste. I had in mind some internal mechanism which would have a setting for how many vertical inches of text you wanted before the bell sounded, some way to register the start of a new page, and after that through the miracles of analog computation it would measure off an appropriate number of platen rotations and ring the bell. If the IBM Selectric can achieve its complex ball dance with all mechanical linkage downstream of the motor such a thing would be trivial for the experienced mechanical designer.

I am going to have to do my own patent search...

Something about air trapped between layers of the sheet and uddenly expelled.  Sounds like the "Bi-Labial Fricative" principle.  If you wanted to, you could devise a system to where the closer the writing lines get to the bottom of the sheet, the higher pitch the sound could be.  And after a point, a light could come on.  Well, just a thought.
 

TypewriterKing wrote:

Just realized this was an old post. It was a fun, fanciful idea and I thought I'd put my 2 cents in.

Heck, it wasn't that old!

I believe you were referring to aeroelastic flutter.