The Addo-X 341E is an electrically driven adding machine. The keyboard has a 10-key number pad with function keys arranged symmetrically around it. There are several variants with regards to the paper feeding mechanism, the most common of which is a simple paper roll. The version here has a wide typewriter style carriage for paper sheets, but also has a spool attached for paper rolls.
The machine allows an input of 10-digit numbers, and has an 11-digit register that handles negative values. To the right of the keyboard is a large plus button which will cause the current input to be printed and added to the main register, after which the input is cleared. The large minus button to the left of the keyboard does the same except that it subtracts and prints the number with a minus sign after it.
The two red buttons at the top right are the Sub-Total and Total buttons. These print the current value of the register in red with a square or asterisk symbol after it. If the (sub)total is negative, there is a A printed after it as well, meaning Credit. In the Total was requested, the register is cleared.
The two red buttons at the top left are used in multiplication, or rather, repeated addition. These two buttons act the same as the minus and plus buttons, except that the input is not cleared. Holding the button down with therefore add/subtract the input repeatedly until the button is released. There is a small switch to the left of these buttons, and if the switch is in the upper position then the Step-O-Matic is activated. This will append a zero to the input whenever one of the multiply buttons is released. An experienced operator can use this to speed up multiplications.
There is a Non-Add button located away from the symmetrical keyboard, and pressing this will print and clear the input without affecting the current totals register, wihch is useful for order numbers or dates.
It has serial number 615,026. The paper feeding mechanism is easily removed by taking out four screws. In that respect it has a similarly modular design as the Burroughs Portable.
A short demonstration of the machine.
The Addo-X 351 adding machine is the successor to the model 341 above. It has the exact same functionality, but has a somewhat improved mechanism and an entirely new case. The buttons are the same, with one extra button that opens the top of the case to give access to the ink ribbon.
It has serial number 426,251. The case is extremely easy to remove. Press the button to flip open the top section. Next to each ink ribbon spool is a small clip, and after they have been pushed aside, the whole upper case can be lifted off.
Aktiebolaget Addo was founded in Malmö in 1918 by Hugo Agrell. He had been a salesman, mostly of American and German calculators. When the first world war made the import of these machines more difficult, he had the idea to make Swedish adding machines. His cousin Oscar Prinz was a mechanical engineer, and together they started the Addo company. At first they made machines similar to the Comptator, but then improved on it and added a printing mechanism. From about 1928 they made full keyboard adding listing machines of their own design, and from about 1935 they made machines with 10-key numeric input, named Addo-X.
In 1966 Addo was bought by Facit-Odhner. Facit was slow to merge with Addo, so the two production lines ran simutaneously for a while, essentially competing with each other. This became more problematic when cheap electronics rapidly changed the market for calculators. Addo/Facit was unable to adapt quickly enough, and in 1973 was sold off to Electrolux. Production of the last Addo adding machines ended a year later.
Only models made by Addo will be listed here. Not included are the adding machines made by the daughter company Dixma from 1939 onwards. These were sold under the brand name DIXI and had a Dalton-style keyboard. Also not listed here are the Multo pinwheel calculators.
Addo started out making a relatively simple adder that was similar to the Comptator, an adder based on the Rapid Computer. The first four Addo models were based on this, all using sliders that the user moves with a stylus.
|Addo 1||1918-1920?||9||Like Comptator, metallic.|
|Addo 2||1920-1926||10||On a wooden or later metal base; black finish.|
|Addo 3||1920?-1926||10||As Addo 2, but for British currency.|
|Addo 4||1924-1926||10||As Addo 2, with printing mechanism.|
|Addo 5||1924-1926||10||As Addo 4, but for British currency.|
|Addo 9||9×9||British currency, up to £999,999 19s 11d.|
|Addo 10||9×10||British currency|
|Addo 206||9×9||Like Addo 6 but with extra memory register. Probably first made in about 1940|
|Addo 207||9×10||Like Addo 7 but with extra memory register. Probably first made in about 1940|
|Addo 307||9×10||Like Addo 7 but can handle negative totals. Probably first made in about 1940|
|Addo-X 30||9×9||These seem to be simplified versions of the series 20 that have no subtraction.|
|Addo-X 321||10×11||Like Addo-X 21 but can handle negative totals|
|Addo-X 40||9×9||These are the base models, which have a register that cannot handle negative totals, and often manual rather than electric|
|Addo-X 241||10×11||This has an extra totaliser register for adding together the totals from the main register. Neither register handles negative totals.|
|Addo-X 341||10×11||The main register can handle negative totals, with an indicator window above the 9-key that shows the sign.|
|Addo-X 441||10×11||This has an independent extra register. Neither register handles negative totals.|
|Addo-X 541||10×11||This has an extra totaliser register for adding together the totals from the main register. Both registers handle negative totals.|
|Addo-X 741||10×11||This has an independent extra register. Both registers handle negative totals.|
|Addo-X 2341||10×11||As 341 but with multiplier keys implementing shortcut multiplication.|
|Addo-X 3341||10×11||As 341 but with multiplier keys, moving decimal point|
|Addo-X 3541||10×11||As 541 but with multiplier keys, moving decimal point|
|Addo-X 4341||10×11||As 341 but with automatic division|
|Addo-X 4541||10×11||As 541 but with automatic division|
|Addo-X 152||8×8||Base electric model, register without negative totals.|
|Addo-X 154||9×10||Base electric model, register with negative totals.|
|Addo-X 351||10×11||Negative totals, step-o-matic,|
|Addo-X 653||12×13||Extra totaliser with negative totals.|
|Addo-X 2353||12×13||Negative totals, multiplier keys|
|Addo-X 3653||12×13||Extra totals register with negative totals, multiplier keys.|
|Addo-X 4653||12×13||Extra totals register with negative totals, multiplier keys, Automatic division|
|Patent||Filing date||Publish date||Name||Description|
|CH 196,009||16-03-1937||28-02-1938||Aktiebolaget Addo||Repeated addition mechanism|
|DE 913,830||11-01-1952||21-06-1954||Aktiebolaget Addo; Rolf Bertil Andrén||Repeated addition mechanism|
|GB 756,772||09-04-1954||12-09-1956||Aktiebolaget Addo||Adding machine improvements|
|DE 960,771||08-01-1953||28-03-1957||Aktiebolaget Addo; Thure Bernhard Bogert||Printer carriage control
See also: CH 311,851
|DE 1,097,186||21-03-1956||12-01-1961||Aktiebolaget Addo; Gösta Roland Holmström; Ove Gustaf Klingström||Shockabsorber for input mechanism
See also: US 2,985,363
|DE 1,145,394||21-08-1956||14-03-1963||Aktiebolaget Addo; John Lydfors||Printing of multiplier digits
See also: US 3,016,188
|DE 1,196,883||29-11-1955||15-07-1965||Aktiebolaget Addo; John Lydfors||Multiplier keys|
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