Curta calculator - AbsoluteAstronomy.com

The Curta is a small, hand-cranked mechanical calculator

Calculator

An electronic calculator is a small, portable, usually inexpensive electronic device used to perform the basic operations of arithmetic. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.The first solid-state electronic...

introduced in 1948. It has an extremely compact design: a small cylinder that fits in the palm of the hand. It can be used to perform addition, subtraction, multiplication, division, and — with more difficulty — square roots and other operations. The Curta's design is a descendant of Gottfried Leibniz

Gottfried Leibniz

Gottfried Wilhelm Leibniz was a German philosopher and mathematician. He wrote in different languages, primarily in Latin , French and German ....

's Stepped Reckoner

Stepped Reckoner

The Step Reckoner was a digital mechanical calculator invented by German mathematician Gottfried Wilhelm Leibniz around 1672 and completed in 1694. The name comes from the translation of the German term for its operating mechanism; staffelwalze meaning 'stepped drum'...

and Thomas

Charles Xavier Thomas

Charles Xavier Thomas de Colmar was a French inventor and entrepreneur best known for designing, patenting and manufacturing the first commercially successful mechanical calculator, the Arithmometer and for founding the insurance companies "Le Soleil" and "L'aigle" which, under his leadership,...

's Arithmometer

Arithmometer

An Arithmometer or Arithmomètre was a mechanical calculator that could add and subtract directly and could perform long multiplications and divisions effectively by using a movable accumulator for the result. Patented in France by Thomas de Colmar in 1820 and manufactured from 1851 to 1915, it...

, accumulating values on cog

Cog

Cog may refer to:* A part of a gear system* Cog , a small sailing vessel* A tenon that extends all the way through another piece of wood, in joinery* The evil robots in Toontown Online...

s, which are added or complemented by a stepped drum

Stepped Reckoner

mechanism.

History

The Curta was conceived by Curt Herzstark

Curt Herzstark

Curt Herzstark was born on July 26, 1902 in Vienna, and died October 27, 1988 in Nendeln, Liechtenstein. During World War II, Curt Herzstark's plans for a mechanical pocket calculator literally saved his life....

(1902–1988) in the 1930s in Vienna

Vienna

Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

, Austria

Austria

Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

. By 1938, he had filed a key patent, covering his complemented stepped drum, Deutsches Reichspatent (German Empire Patent) No. 747073. This single drum replaced the multiple drums, typically around 10 or so, of contemporary calculators, and it enabled not only addition, but subtraction through nines complement math, essentially subtracting by adding. The nines' complement math breakthrough eliminated the significant mechanical complexity created when "borrowing" during subtraction. This drum would prove to be the key to the small, hand-held mechanical calculator the Curta would become.

His work on the pocket calculator stopped in 1938 when the Nazis forced him and his company to concentrate on manufacturing measuring instruments and distance gauges for the German army.

Herzstark, the son of a Catholic mother but Jewish father, was taken into custody in 1943, eventually finding himself at the Buchenwald concentration camp

Buchenwald concentration camp

Buchenwald concentration camp was a German Nazi concentration camp established on the Ettersberg near Weimar, Germany, in July 1937, one of the first and the largest of the concentration camps on German soil.Camp prisoners from all over Europe and Russia—Jews, non-Jewish Poles and Slovenes,...

. Ironically, it was in the concentration camp that he was encouraged to continue his earlier research: "While I was imprisoned inside [Buchenwald] I had, after a few days, told the [people] in the work production scheduling department of my ideas. The head of the department, Mr. Munich said, 'See, Herzstark, I understand you've been working on a new thing, a small calculating machine. Do you know, I can give you a tip. We will allow you to make and draw everything. If it is really worth something, then we will give it to the Führer as a present after we win the war. Then, surely, you will be made an Aryan.' For me, that was the first time I thought to myself, my God, if you do this, you can extend your life. And then and there I started to draw the CURTA, the way I had imagined it."

Herzstark worked hard to move his invention from his knowing how to build the device "in principle" to concise working drawings for a manufacturable device.

The department head's celebration plan did not materialize, but Herzstark's construction plans did. Between April 11, 1945, when Buchenwald was liberated by the Americans

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, and the following November, Herzstark was, after making only a few "detailed improvements" to the design, able to locate a factory in Sommertal, near Weimar

Weimar

Weimar is a city in Germany famous for its cultural heritage. It is located in the federal state of Thuringia , north of the Thüringer Wald, east of Erfurt, and southwest of Halle and Leipzig. Its current population is approximately 65,000. The oldest record of the city dates from the year 899...

, where machinists were skilled enough to work at the necessary level of precision, and walk away with three working models of the calculator.

The Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

ns had arrived in July, and Herzstark feared being sent to Russia, so, later that same month, he fled to Austria. He began to look for financial backers, at the same time filing continuing patents as well as several additional patents to protect his work. The Prince of Liechtenstein

Liechtenstein

The Principality of Liechtenstein is a doubly landlocked alpine country in Central Europe, bordered by Switzerland to the west and south and by Austria to the east. Its area is just over , and it has an estimated population of 35,000. Its capital is Vaduz. The biggest town is Schaan...

eventually showed interest in the manufacture of the device, and soon a newly-formed company, Contina AG Mauren, (aka Contina Ltd Mauren) began production in Liechtenstein.

It was not long before the financial backers, apparently having gotten from him all they thought they needed, contrived to force him out by reducing the value of all existing stock to zero, including his one-third interest in the company. These were the same people who, earlier, had elected not to transfer ownership of the Herzstark's patents to the company, so that, should anyone sue, they would be suing Herzstark, not the company, thereby protecting themselves at Herzstark's expense. This ploy now backfired: without the patent rights, they could manufacture nothing. Herzstark was able to negotiate a new agreement, and money continued to flow to him.

Curtas were considered the best portable calculators available until they were displaced by electronic calculators in the 1970s. Herzstark continued to make money from his invention until that time, although, like many inventors before him, he was not among those who profited the most from his invention. The Curta, however, lives on, being a highly-popular collectible, with thousands of machines working just as smoothly as they did 40, 50, and 60 years ago when they were manufactured.

Description and use

Numbers are entered using slides (one slide per digit) on the side of the device. The revolution counter and result counter appear on the top. A single turn of the crank adds the input number to the result counter, at any position, and increments the revolution counter accordingly. Pulling the crank upwards slightly before turning it performs a subtraction instead of an addition. Multiplication, division, and other functions require a series of crank and carriage-shifting operations.

The Curta was affectionately known as the "pepper grinder" or "peppermill" due to its shape and means of operation. It was also termed the "math grenade", due to its superficial resemblance to a certain type of hand grenade.

Curta Type I and Type II

The Type I Curta has 8 digits for data entry (known as "setting sliders"), a 6-digit revolution counter, and an 11-digit result counter. According to the advertising literature, it weighs only 8 ounces (about 230 grams). Serial number 70154, produced in 1969, weighs 245 grams.

The larger Type II Curta, introduced in 1954, has 11 digits for data entry (known as "setting sliders"), an 8-digit revolution counter, and a 15-digit result counter. It weighs 13.15 ounces or 373 grams, based on weighing serial number 550973, produced in early 1966.

An estimated 140,000 Curta calculators were made (80,000 Type I and 60,000 Type II). According to Curt Herzstark, the last Curta was produced in 1972.

Use in car rallies

The Curta was popular among contestants in sports car rallies during the 1960s, 1970s and into the 1980s. Even after the introduction of the electronic calculator for other purposes, they were used in time-speed-distance (TSD) rallies to aid in computation of times to checkpoints, distances off-course, etc., since the early electronic calculators did not fare well with the bounces and jolts of rally racing.

Contestants who used such calculators were often called "Curta-crankers" by those who were limited to paper and pencil, or who used computers linked to the car's wheels.

Curta calculators contributed to the saying when describing the process of calculating, "Cranking out the answer."

Use by pilots

The Curta was also favored by both commercial and general-aviation pilots, before the advent of electronic calculators, because of both its precision and the user's ability to confirm the accuracy of his or her manipulations via the revolution counter. Because calculations such as weight and balance are critical for safe flight, precise results free of pilot error are essential.

Cost

The Curta Type I was sold for $125 in the later years of production; the Type II was sold for $175. While only 3% of Curtas were returned to the factory because of repairs under warranty, a small, but significant number of buyers returned the Curta in pieces. Many purchasers attempted to disassemble the Curta. Reassembling the machine was more difficult as assembly required intimate knowledge of the orientation and installation order for each part and sub-assembly, plus special guides designed to hold the pieces in place during assembly. Many identical looking parts, each with slightly different dimensions, required test fitting and selection as well as special tools to adjust tolerances.

In current activity

The Curta calculator was chosen to be a high value (48 point) item for the 2011 University of Chicago Scavenger Hunt
University of Chicago Scavenger Hunt
The University of Chicago Scavenger Hunt is an annual four-day team-based scavenger hunt held at the University of Chicago, USA, in May.- Overview :...

.

In media

The Curta is featured in the novel Pattern Recognition
Pattern Recognition (novel)
Pattern Recognition is a novel by science fiction writer William Gibson published in 2003. Set in August and September 2002, the story follows Cayce Pollard, a 32-year-old marketing consultant who has a psychological sensitivity to corporate symbols...

by William Gibson, where one of the minor characters has an interest in them.
The Curta is also the subject of an article by Cliff Stoll
Clifford Stoll
*High-Tech Heretic: Reflections of a Computer Contrarian, Clifford Stoll, 2000, ISBN 0-385-48976-5.-External links:* at Berkeley's Open Computing Facility**, December 3, 1989* copy at Electronic Frontier Foundation, May 1988...

in the January 2004 edition of Scientific American
Scientific American
Scientific American is a popular science magazine. It is notable for its long history of presenting science monthly to an educated but not necessarily scientific public, through its careful attention to the clarity of its text as well as the quality of its specially commissioned color graphics...

.
The Curta is on the Popular Science
Popular Science
Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...

magazine list of Top 100 pieces of retro technology.
A Curta is sold to the Gold & Silver Pawn Shop in Las Vegas in "Spidey Cents", a fourth season episode of the History reality television
Reality television
Reality television is a genre of television programming that presents purportedly unscripted dramatic or humorous situations, documents actual events, and usually features ordinary people instead of professional actors, sometimes in a contest or other situation where a prize is awarded...

series Pawn Stars
Pawn Stars
Pawn Stars is an American reality television series on the History Channel, produced in Manhattan by Leftfield Pictures. The series is filmed in Las Vegas, Nevada, where it chronicles the daily activities at the Gold & Silver Pawn Shop, a 24-hour family business operated by patriarch Richard...

, which aired in May 2011.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.