Re: To David Soderman: A Little Test

["Ernst Dinkla" <E.Dinkla@xxxxxxxxx>]

----- Original Message -----
From: <rafe.bustin@verizon.net>
To: <scan@leben.com>
Sent: Thursday, April 11, 2002 10:11 PM
Subject: Re: To David Soderman: A Little Test


> On 11 Apr 2002 at 15:21, Ernst Dinkla wrote:
>
> > I never had the 8000 open so I wonder how the film carrier
moves
> > while it scans. It can't be by the gearing teeth at the side
of
> > the carrier one would think. Is there a more sophisticated
> > mechanism inside ?
> >
> > I always thought that by the gearing teeth at the side the
> > carrier is pulled in and positioned and after that a scan
unit
> > moves below the single frame to scan it. Never paid attention
to
> > what it actually does.
>
>
>
> Both good questions and observations.  Frankly, the
> mechanics of the LS-8000 leave me wondering and,
> well, a bit nervous.
>
> If you look very closely you'll see that it is indeed
> that big massive film holder that's being moved
> during the scan.
>
> I too have observed those big gear-teeth on the
> side (edge) of the film holder and wondered about
> their purpose.
>
> Is it possible that the gear teeth are used during
> loading/unloading of the carrier only?
>
> Is it possible that the gear teeth are in any way
> related to the banding?  (The spacing of the gear
> teeth and the spacing of the bands is quite
> different.)

The scan movement can't be done with the gear-teeth and a gear
wheel. The only workable solution possible that includes the gear
teeth of the carriage could be a belt that fits in the gear teeth
over a longer stretch and the belt itself driven by friction or
very fine teeth on the inside. But most likely the carrier is
clamped between some wheels and relies on friction movement only
for the scan movement.
If it still has to move the uncoupled gear wheel then that in
itself could be a source of vibration.

The weight difference between the carriages is considerable,
their length varies as well so a rack and pinion kind of movement
with teeth of that size isn't an option. I have seen better gear
solutions on 19 th century canal locks. I'm tempted to open the
scanner as my plan to make another type of glass carrier should
be compatible with the scan mechanism in all aspects. Maybe
tomorrow.

Ernst



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