The Mercedes driving mechanism
The principle of the driving mechanism of the Mercedes calculators is illustrated in the following animation. The digit "5" is entered on the keyboard and consequently the gear has shifted from his rest position to the fifth toothed rack.
During the first half turn of the driving wheel, the toothed rack is engaged with the numeral wheel and the accumulator increases by five. When the toothed rack comes back the numeral wheels are disengaged and the accumulator content does not change. In fact this illustration simplifies the mechanism and the disengagement does not take place at the toothed racks location.
Clic on the links hereafter to see movies of the toothed racks and engagement/disengagement sytems.