Jaap Scherphuis | The proportional lever mechanism of the Mercedes-Euklid calculators @jaapsch2 | Uploaded November 2019 | Updated October 2024, 1 hour ago.
Mercedes-Euklid calculators use a mechanism invented by Christel Hamann in about 1906, called proportional levers. It uses 10 toothed racks that shift by amounts ranging from 0 to 9. By shifting a gear along an axle to engage with a chosen rack, the axle is rotated by the chosen amount.

To see the Mercedes-Euklid in its normal assembled condition see my other video:
youtube.com/watch?v=aVFtFHLIrYM

Christel Hamann also invented the Hamann Manus shown in this video:
youtube.com/watch?v=dApNR6drlY4

For more information about this mechanical calculator or the others in my collection, visit my site:
jaapsch.net/mechcalc

0:00 Introduction
0:11 Removing casing
1:04 Toothed rack mechanism
2:09 Keyboard input
3:52 Subtraction
5:38 Outro