Addimat
Schnellrechner
Video
History
Newspaper and Magazine Advertisements
Patents
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The Addimat is a simple 7-digit adder which was made in Italy from the mid 1950s until the late 1960s. It was also sold with the name Addipresto.
A 7 digit register is visible in a row of round window holes along the top of the machine. Below this are seven vertical slots, partially exposing the rims of the seven number wheels inside. The numbers 1 to 9 are printed next to the slots. The machine comes with a stylus, and when it is placed in the slot next to a printed digit and then moved down to the bottom, the chosen digit is added at that place in the register. When a digit exceeds 9, the wheel to the left is automatically incremented. To add a sequence of numbers, simply enter the numbers one at a time and the register will show the total.
The red lever on the left clears the register.
Here is an instruction leaflet for the Addimat which explains its use in German, French, and Dutch.
The mechanism is fairly simple. Each number wheel is also a cam wheel, and pushes back on a spring-loaded carry pawl that engages with the next wheel. Just after the digit 9 the cam track drops back causing the pawl to be released and push the next wheel up one step. This system is cleverly reused for the clearing mechanism. When the red lever is pulled, all the pawls are lifted from the wheels, but the spring-loaded arms of the carry pawls still push back on the cam wheels, causing them to return to zero.
The Schnellrechner is an exact copy of the later versions of the Addipresto. It even uses plastic of the same light-blue colour for the casing, and red for the stylus and clearing lever. It was made by Swift Business Machines Corp. in Hong Kong in the 1960s and up until about 1975. The same model was also sold under the name Swift Handy Calculator.
Apart from the extra hole on the top right for the stylus, the only real difference between this machine and the Addimat above is that it has a set of complemetary digits next to the slots to aid with subtraction. To subtract a number, enter it using the small red complementary digits, including entering leading zeroes for all the columns to the left of the number. Then add an extra 1 (normal digits). For example, to subtract 2 you need to enter the number 0000002 in red digits and add 1. This in effect adds 9999997+1=9999998, which causes the register to roll over to the correct result.
Below is a video I made that demonstrates the Addimat adding macine and the Schnellrechner.
This kind of adder was first invented by Carlo Fossa-Mancini in the 1890s (patents IT42837 in 1896, FR272735 in 1897, and GB 1899/04489 in 1899). He had it manufactured in the factories of Japy Frères & Cie in France, and sold them with the name Indispensable. It seems it was not a success and only a few hundred were made.
The idea was revived when Sergio Lanza patented his design in 1956 (IT554094), though I have not been able to find a digital copy of that patent. Sergio Lanza founded a company called Brevetti Lanza, based in Savona Italy. As the company name implies, it manufactured Lanza's patented inventions, including this adder. I think it was sold under the name Addipresto in Italy, but as Addimat in most of the rest of Europe. It seems that in the USA the machine was only sold under the name Addipresto. From around 1964 the Addimat name was no longer used.
From the mid 1960s cheap copies were made in Hong Kong by the Swift Business Machines Corp. These were sold under various names, such as the Swift Handy Calculator, and the Schnellrechner shown above. They could do so because Lanza had neglected to patent the adder outside of Italy. The copies outcompeted the original, and Brevetti Lanza stopped making its adder.
Here are some of the advertisements I found in online archives.
The Addipresto was apparently patented by Sergio Lanza on 14-06-1956, IT554094, but it
is not available in the Espacenet database.
A very similar machine was however patented by an Italian more than half a century earlier:
| Patent | Filing date | Published date | Name | Description |
|---|---|---|---|---|
| GB 1899/04489 | 01-03-1899 | 01-07-1899 | Carlo Fossa-Mancini | An Improved Adding Apparatus |
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