Olivetti Tetractys 24 Electric Printing Calculator
Calculatrice électrique imprimante tout automatique dans les 4 opérations
Vierspecies-Rechenmaschine mit Druckwerk
The Tetractys, introduced in 1956 with the Divisumma 24, was derived from the latter
with the addition of various features, including a double totalizer. Thanks to the memory and the two totalizers, it was possible to move from one
operation to the next while retaining the products and quotients of the previous calculation.
Another distinctive feature of the Olivetti Tetractys is the abridged multiplication, an advanced mechanical calculation technique
designed to reduce the number of machine cycles, and therefore the calculation time. It involves optimizing the input of the multiplier by breaking
down each digit into addition or subtraction with respect to a base of 10, rather than using only repeated addition. For example, to multiply
by 9, instead of 9 additions, the machine does one 10 addition (10 x Y) then one 1 subtraction (1 x Y), which is
much faster.
So, the Tetractys represented the state of the art in mechanical calculation at the time. It was a highly complex machine:
a tangle of levers, springs, shafts, and cams (about 1,500 parts in total in a single machine) moved rapidly to automatically perform complex
calculations.
The mechanism was designed by Natale Capellaro, while the body is due to Marcello Nizzoli.
Olivetti Tetractys Brochures: French,
German, Italian.
Some patents:
• GB787893 - Improvements in or relating to Multiplication Mechanisms for Calculating Machines.
• US2902124 - Operating Mechanism for Power Driven Business Machines.
• US2821342 - Dividend Divisor Aligning Mechanism for Computing Machines.
Videos on YouTube:
• 1956 Olivetti Tetractys running without body
• Olivetti Tetractys
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