Hello,

I own six Curtas now - one of those calculators is special, because it does not make this typical sound. It has an additional ring (spring), which lifts the catch (that prevents from turning in the wrong direction) when turning the crank handle.
Does anyone of you have further information on this "silent" Curta?
How many were produced?
I only know of one other silent Curta which is a Type I.

Regards

Sebastian

https://www.flickr.com/photos/131105513@N02/16404073206

Hi Sebastian,

I don't know much about them - one was sold on ebay not so long ago. The question I keep asking myself is - if a spring holds back the ratchet pawl, what prevents the machine from turning backwards ?

Thanks,

Cris

Hi Cris,

as soon as you try to turn the crank backwards, this ring (spring) also turns backwards a bid and lowers the catch again…

Sebastian