Olivetti Divisumma 24

The calculating mechanism was designed by engineer Natale Capellaro, and the exterior by the noted architect and industrial designer Marcello Nizzoli. The machine first appeared in 1948 as the manually-operated Divisumma 14, in a casing similar to the Elettrosumma 14. The machine was extensively redesigned in 1956 to become the Divisumma 24, which continued in production in various forms well into the 1960s. the Olivetti Divisumma 24 allowed users to quickly perform basic arithmetic operations such as addition, subtraction, multiplication, and division. The machine operated at a speed of 250 cycles per minute, powered by a 70-watt motor. Each phase of a calculation, as well as each result, could be automatically printed on a roll of paper using an inked ribbon in blue and red, making it a useful tool for record-keeping and reviewing calculations. The Divisumma 24 was designed for ease of use, with a numeric keypad reduced to ten keys to set all the terms of the operation. This simplicity, along with the ability to print the results, made its mode of use almost completely analogous to that of the current office calculators of its time. It was a simplified and less expensive version of the complete basic project, namely the Tetractys, which allowed it to achieve high sales figures—about 6 million units—making it the most sold model by Olivetti. The Divisumma 24 was part of the MC-24 series, which also included the Elettrosumma 22, the Elettrosumma 24, the Multisumma 24, and the Tetractys, all of which were equipped with a dynamic memory and an integrated print register. In terms of construction, the Divisumma 24 featured a cast iron base for stability, with sheet metal flanges to support the main shaft and other components. The internal mechanisms, made of iron and steel, consisted mainly of levers moved by cams made from synthesized material with a tempered sliding area. The assembly was primarily done with screws, and the machine was known for its durability and reliability.