Uploaded May 2021 | Updated September 2026, 1 hour ago

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The EOS calculator is identical to the Hannovera CK calculator. It uses an oscillating segment system somewhat similar to the Demos, but whereas the Demos uses complementary digits for subtraction, the EOS allows you to simply turn the crank in the opposite direction like a pinwheel machine. About 1000 were produced, and sold in Switzerland.

I demonstrate the EOS in the following video: youtu.be/_bmuSqlPrL8

For more information on this and other calculators in my collection, please visit my website:
jaapsch.net/mechcalc

0:00 Introduction
0:39 Addition cycle
3:28 Subtraction cycle
5:11 Oscillating mechanism
5:40 Counter mechanism
7:07 Automatic input clearing
7:52 Clearing output register
8:17 Cam wheels
9:24 Outro