Re: To David Soderman: A Little Test

["Dave King" <kingphoto@xxxxxxxxxxxxxx>]

----- Original Message -----
From: "Ernst Dinkla" <E.Dinkla@chello.nl>
To: <scan@leben.com>
Sent: Thursday, April 11, 2002 5:40 PM
Subject: Re: To David Soderman: A Little Test


>
> ----- 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


If you do get in there could you also have a look at the mirror(s)
positions?  Wondering if they're user accessible for the inevitable day they
need cleaning.

Dave


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