Leibniz wheel

A Season roller is a cylinder, on the nine different long teeth are applied. It is certain mechanical calculators as a drive.

Principle of operation

The illustrated below the stepped drum slide gear (so-called transmission gear, here red) is connected with the setting dial of the calculating machine. If the digit 0 is set, this gear is located on the left edge of the stepped drum, if one has been set 9, corresponding to the right margin.

The number of meshing teeth of umdrehenden stepped drum corresponds to the set number. If the set to 0, so the transmission gear is not rotated, as on the left edge of the stepped drum is no tooth. 5 is set to engage with five teeth, and the remaining four are short so as to engage.

Historical development

The first calculating machine after the season rolling principle developed Gottfried Wilhelm Leibniz ( 1646-1716 ). The principle he introduced in 1673 by the Royal Society in London. The developed machine it was almost ready for use, that is, on her some sample tasks were calculated for functional testing.

The development work on the first usable computing machine of Württemberg minister Philipp Matthäus Hahn (1739-1790) began in 1770. It was completed in 1774 and presented to the public. Total produced Hahn and his brother Schuster 8 to 12 machines.

Knowing a brief description of Rooster 's machine of Hesse Johann Helfrich von Müller (1746-1830) developed a similar calculator. Its construction had some improvements. So they had a bell that rang when capacity is exceeded, and it could easily be converted for computing in non-decimal number systems. In addition to the construction, Müller dealt with the machine arithmetic. He compared this with the calculation with pen and paper and came to the conclusion that the machine arithmetic is rational.

Standard Season rolling machines were first probably made ​​by Charles Xavier Thomas (1785-1870) from 1820. Until 1878 about 1500 machines were produced in his factory.

The relay roller principle was at the industrially manufactured calculators in competition with the Sprossenradprinzip. Even after the Second World War, calculating machines both functional principles have been established. An example of the Season roller type is constructed by Curt Herzstark pocket calculator Curta ( 1946-1972 ).