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Danaddo adding machine

The Danuvia Danuvia Bel- és Külkereskedelmi Rt. (Danuvia Home and Foreign Trade Joint-Stock Company), later renamed to Danuvia Ipari és Kereskedelmi Rt. (Danuvia Industrial and Commercial Company) was established in 1920. In 1923 they started to produce aircraft machine guns based on Ferenc Gebauer's invention, and some tools. From 1938 only weapons were produced. The production machines were dragged away by retreating german forces, and the changed politics forces Danuvia to manufacture different goods e.g. alarm clocks, toys and mousetraps. The company was nationalized in 1948. From 1954, they produced motorbikes (to 1963), and increasing quantities of different tools and machines.
The Danaddo After the World War II, Danuvia decided to plan office equipments - portable typewriters and calculators, but only a small addiator-like calculator was suitable for production. This machine is an
Manufacturing of Pocket adders is starting
A new type of pocket calculator will be produced at Danuvia Industrial and Commercial Company. The new calculator called "Danaddo" issues with elegant, pocket-suitable construction. The calculator can solve addition and subtraction for eight digits, and has a great advantage to usable for any non-decimal operations too.
(Népszava, 2 April 1949.)
The produced version in contrast to this article has the capacity of 9 digits and not suitable for calculating with non-decimal units.

This kind of calculator is actually an improved version of gear bar adding machines: those has grooves turning back for guiding the stick to advance the next gear bar, the Danaddo has straight grooves with gear wheels which only rotates at the last position advancing the next gear bar automatically. The gear bars are built with steel springs which inhibit stopping between correct positions. For changing the operation from addition to subtraction and vice versa there is a movable aluminium board which masks the gaps are only for the other operation. If arrows are appearing in the place of digits, the gear wheel mechanism inhibits changing operation. The stick can be placed between the clearing lever and the body.

Usage Chaning operation:: Addition is the default setting. The operation chosen always appears in the middle top of the machine: (+ or - sign). For subtraction the handle in the left must be pulled out.

Addition, subtraction: The stick inserted to a hole next to the corresponding digit must be pulled down or pulled up, if the bar around the hole has red marking.

Arrows appearing: If arrows appear in place of digits, the corresponding gear bar must be pulled in the direction showed the arrow. (Multiple ten-carry)

Clearing: The clearing handle must be pulled up while all digits changes to zero.

Technical specifications
Manufacturer: Danuvia Ipari és Kereskedelmi Rt.
Mfg. date: 1949
Size: 124×156×12 mm
Material: aluminium
Capacity: 9 digits (for input and result)
Operating method: gear bars with single automatic ten-carry
The machine is set for subtraction.

Inside the machine: the gear bars with the gear wheels for ten-carry and guiding the bars can be seen near the missing gear bar.

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