Dave Tweed wrote:

>> Something like routing them all through some springs or so hanging from
>> the ceiling. The tricky thing here is that the force these "springs" apply
>> to the cables has to be constant (that is, independent of the extension of
>> the "spring"), and should be adjustable. I'm not sure such a thing exists.
> 
> Sure, they're quite common. Just Google for "constant force spring".

Thanks... knowing the right term is worth a lot :)

> In fact, you may find that the cheap little pocket tape measures from your
> local hardware store will meet your needs just fine.

Good idea. Worth a try...

> They aren't typically "adjustable", however. But then, ordinary springs
> with adjustable spring constants are rather rare, too. But perhaps you
> could add an adjustable amount of drag to the mechanism to compensate.

If you mean with "drag" a friction on the outgoing part of the spring,
that's probably not really helpful. While it reduces the retracting force
of the spring, it also increases the force needed to pull the cable. 


Howard wrote:

> A servo-controlled winch?  :-)

Maybe instead simply a small DC motor. Should give me an adjustable force;
at least at the stall point, and since the force decreases with increasing
speed, that's probably not a practical problem. 

Thanks,
Gerhard

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