Mechanical calculator for estimating salary deductions - uses outer and inner rotatable discs and cursor to calculate e.g. income tax, social security, and net salary

摘要

The calculator is similar in construction to the circular slide rules which were produced in the 1960s. It has an outer disc (1), a smaller diameter inner disc (2) and a radial cursor arm (3). The three components can each be rotated independently about a central pin, to make calculations. In addition to scales calibrated in thousands of guilders, the discs having engraved legends, relating to the personal taxation and social security circumstances of the subject and his taxation tariff groups. The inner disc (2) also has 'windows', through which other data can be read off the outer disc. @(11pp Dwg.No.4/5)@.