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Olivetti

Olivetti Summa 15

The Olivetti Summa 15 is a manual adding listing machine with a 10-key keyboard. It has an 11-digit register, and allows 10 digits of input. Four function buttons have been combined into a unique four-way button reminiscent of a joystick. This button can be flicked with the thumb of the right hand just before you pull the lever. Depending on which direction the button is moved, a different function is performed - Total (∗ up), Subtotal (⋄ down), Subtract (- right), or Non-add (⊲ left). There is a small tab to the right of the keyboard which is used to release the four-way button if it was accidentally pushed in the wrong direction.

There is cover that is easily removed, giving access to the ink ribbon. The machine takes a standard half-inch wide two-colour ink ribbon. The serial number is only found inside, etched into the metal base of the mechanism. The number of this machine is 366,286.

Video

Below is a video I made that demonstrates the Olivetti Summa 15.

History

The company was founded by Camillo Olivetti in 1908 in Ivrea, a village near Turin, Italy. Initially they made typewriters, but started on adding machines in 1934. Camillo's son, Adriano Olivetti, became chairman in 1938 and was responsible for the company's focus on innovation and design, and for the expansion of its international subsidiaries and sales. In 1959 it even acquired the major american typewriter company Underwood.

Even as Olivetti was making mechanical calculators and adding machines, it was also researching electronics, making Italy's first commercial electronic computer, the Elea 9003 in 1959. After the death of Adriano Olivetti in 1960, Olivetti's lack of leadership and the cost of the Underwood takeover caused financial difficulties, and the electronics division was spun off to a separate company and sold to General Electric.

In the 1970s a renewed focus on small electronics and transition away from purely mechanical machines allowed the company to survive, but the heavy cost of this transition again put the company in financial difficulties. Carlo De Benedetti bought a stake in the company in 1978 and managed the company through its recovery. They developed new electronic products, including in 1982 the first Olivetti personal computer. They did not leave mechanics behind completely, but used their expertise in the development of printers, fax machines, and photocopiers. In the 90s they moved into the telecommunications business, buying the majority of Telecom Italia in 1999, and eventually merging with it in 2003. Currently Olivetti exists as a subsidi

Models

Olivetti's models were generally given successive model numbers, though it seems that some model numbers were skipped or never released, and some of the later model numbers were released out of order. They were also often given names depending on the general type of machine, occasionally with a suffix of a few letters or a word to describe the exact variant.

Below is a partial list of models, taken from Rechner Lexikon. The production years are only approximate.

Manuals

Gebrauchsanleitung für die Olivetti Multisumma 22 elektrische schreibende Rechenmaschine     (PDF, 13.6 MB or archive.org)
Ing. C. Olivetti & C., S.p.A.
1958?
56 page spiralbound booklet
148mm × 210mm

This is the German manual for the Multisumma 22 adding machine. The booklet has no copyright date, but this model was made from 1958.

Gebrauchsanleitung für die schreibende Addiermaschine Olivetti Summa Prima 20    (PDF, 3.91 MB or archive.org)
Ing. C. Olivetti & C., S.p.A.
1960-1970?
32 page combbound booklet
86mm × 124mm

This is the German manual for the Summa Prima 20 adding machine. The booklet has no copyright date, but this model was made approximately between 1960 and 1974.

Gebrauchsanleitung für die elektrische, schreibende Additionsmaschine Olivetti Quanta    (PDF, 4.35 MB or archive.org)
Ing. C. Olivetti & C., S.p.A.
1960-1970?
32 page combbound booklet
85mm × 121mm

This is the German manual for the Summa Quanta 20 adding machine. The booklet has no copyright date, but this model was made approximately between 1961 and 1974.

Articles

Here is a selection of short articles about Olivetti's calculators.

Long article about Olivetti's design
(1961-11 Industrial Design)

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Patents

This is a selection of the Olivetti patents related to calculators.

Links

• Olivetti still exists, though it is a small subsidiary within the TIM group. It still supplies a small selection of calculators.
• John Wolff's Web Museum has a page with a great selection of Olivetti machines.
• Rechner Lexikon has a page about Olivetti, which links to separate pages for various models including the Summa 4, Summa 15, Summa Prima 20, Divisumma 24, and many others.
• Rechenmaschinen Illustrated has a few Olivetti machines.
• Christian Hamann has a Summa Prima 20, a Divisumma 26 GT, as well as some Olivetti typewriters.
• The Arithmeum has many Olivetti machines in its collection: MC 4M, Elettrosumma 14, Divisumma 14, Summa 15, Summa Prima 20, Summa Quanta 20, Summa Quanta R, Elettrosumma 20, Multisumma 20, Elettrosumma 22, Elettrosumma 23, Elettrosumma Duplex 24 CR, Divisumma 24, Divisumma 24 GT, Tetractys, Tetractys CR, Multisumma 26 GT, Divisumma 26 GT, Logos 27-2, Audit 202, Audit 302, Audit 413, Audit 513, Audit 930.
• Vintage Calculators Web Museum has a some Olivetti machines.
• Grumpy Tim's YouTube channel has two excellent videos of the Summa Prima 20: Restoration and Demonstration.
• Italian Ways has some nice pictures of the Olivetti Summa 19.

© Copyright 2022 Jaap Scherphuis, mechcalc a t jaapsch d o t net.