Re: Rotary to linear translation - an interesting idea.

I'm with Bertho. Isn't this the same as when figuring pitch diameters for
belts, sheaves, chains etc?

Tom

>>>>>>>>>>>>>>>

Message: 3
Date: Mon, 10 Apr 2000 19:38:16 -0400
From: Bertho Boman <boman@...>
Subject: Re: Rotary to linear translation - an interesting idea.

Jon,
Never mind the crow. As long as we are disagreeing, one of us is wrong and
I like to
learn if it is me (which it very well might be).

I believe there are two ways of thinking about it.
Since we are talking about a ribbon that is not zero thickness we can call
its thickness
center line its average length. If the wheel just touches a flat surface,
wheel diameter
is fine but if the ribbon has been bent, the wheel surface is a distance
away from that
center line: It looks like we added a layer on the wheel to reach the
centerline. The
wheel appears to have a larger diameter and turns slower.

The other way is to think about what happens to the ribbon when it is
curved. One
side will stretch and the other side will compress. The wheel is measuring
the
compressed side of the ribbon and the resultant distance will be slightly
shorter than
the average centerline and again, we will measure a too short distance.
Bertho
<<<<<<<<<<<<<<<