Sponsored Links

Sabtu, 02 Juni 2018

Sponsored Links

Inside a mechanical calculator - Imgur
src: i.imgur.com

mechanical calculators , or calculators , are mechanical devices used to perform arithmetic basis operations automatically. Most mechanical calculators have sizes that are comparable to small desktop computers and have been obsolete by the emergence of electronic calculators.

The surviving record of Wilhelm Schickard in 1623 reveals that he designed and had built the earliest of modern attempts in mechanization calculations. The machine consists of two sets of technologies: the first abacus made of Napier bone, to simplify the multiplication and division first described six years earlier in 1617, and for mechanical parts, it has a call pedometer for additions and subtractions. A study of surviving records shows a machine that gets stuck after multiple entries on the same dial, and it can get damaged if the carry should be propagated over multiple digits (like adding 1 to 999). Schickard abandoned his project in 1624 and never mentioned it again until his death 11 years later in 1635.

Two decades after Schickard's failed attempt, in 1642 Blaise Pascal convincingly solved these particular problems with the invention of his mechanical calculator. Incorporated into his dad's job as a tax collector in Rouen, Pascal designed a calculator to aid in the large amount of required boring arithmetic; it's called Pascal's Calculator or Pascaline.

Thomas' arithmometer, the first commercially successful machine, was produced two hundred years later in 1851; it is the first mechanical calculator that is powerful enough and reliable enough to be used every day in an office environment. For forty years the arithmometer is the only type of mechanical calculator available for sale.

Comptometer, introduced in 1887, was the first machine to use a keyboard consisting of nine key columns (from 1 to 9) for each digit. The Dalton enhancement machine, produced starting in 1902, was the first to have a 10-key keyboard. Electric motors were used on several mechanical calculators from 1901. In 1961, the comptometer type machine, Anita mk7 from Sumlock comptometer Ltd., became the first desktop mechanical calculator to receive all electronic calculator engines, creating links between the two industries. and marked the beginning of its decline. The production of mechanical calculators ceased in the mid-1970s closing down an industry that had lasted for 120 years.

Charles Babbage designed two types of new mechanical calculators, so large that they needed steam power to operate, and that was too sophisticated to build in his lifetime. The first is a mechanical calculator automatic , the difference engine, which can automatically calculate and print mathematical tables. In 1855, Georg Scheutz became the first of a handful of designers to successfully build a smaller and simpler model of the difference engine. The second is a programmable mechanical calculator , the analytical engine, which Babbage began in 1834; "In less than two years he has sketched many prominent features of modern computers.The important step is the adoption of a hollow card system derived from Jacquard looms" making it programmable indefinitely. In 1937, Howard Aiken convinced IBM to design and build the ASCC/Mark I, the first machine of its kind, based on analytic engine architecture; when the machine was finished, some called it "Babbage's dream come true".


Video Mechanical calculator



Ancient history

The desire to save time and mental effort in arithmetic calculations, and to eliminate human responsibility for error, may be as old as arithmetic itself. This desire has led to the design and construction of various tools for calculation, starting with groups of small objects, such as gravel, first used loosely, then as counters on board being mastered, and then still like beads mounted on mounted cables in a frame, as in an abacus. This instrument may be found by Semitic races and later adopted in India, from which it spreads westward across Europe and eastward to China and Japan. After the development of the abacus, no further progress was made until John Napier composed his numbering rod, or Napier's Bones, in 1617. Various forms of Bones appeared, some nearing the beginning of mechanical calculations, but it was not until 1642 that Blaise Pascal gave us the first mechanical counting machine in meaning that the term is used today.

A short list of other precursors to a mechanical calculator should include a group of mechanical analog computers which, once set, are only modified by the continuous and repetitive action of their actuators (crank grip, weight, wheel, water...). Prior to the general era, there were odometers and mechanisms of Antikythera, an unusual place, a unique astronomical clock, followed over a millennium later by an early mechanical clock, an astrolab directed and followed in the 15th century by a pedometer. These machines are all made of toothed teeth connected by some kind of carry mechanism. These machines always produce identical results for identical initial settings unlike the mechanical calculators in which all wheels are independent but are also connected together by arithmetic rules.

Maps Mechanical calculator



17th century

Overview

The 17th century marked the beginning of the history of a mechanical calculator, seeing the discovery of his first machine, including the Pascal calculator, in 1642. Blaise Pascal had created a machine that he presented as capable of performing calculations previously thought to be only humanly possible, but he was unsuccessful in creating industry.

In a sense, Pascal's invention is premature, in which the mechanical art of his time was not advanced enough to allow his machine to be made at an economical price, with the accuracy and strength required for long-term use. This difficulty could not be overcome until the nineteenth century, at which time a new stimulus for discovery was provided by the need for many more complex types of calculations than Pascal considered.

The 17th century also saw the invention of some powerful tools to aid arithmetic calculations such as Napier bone, logarithm tables and slide rules which, for its ease of use by scientists in multiplying and dividing, override and hinder the use and development of mechanics. calculators until the release of the arithmometer's production in the mid-19th century.

Invention of mechanical calculator

Blaise Pascal created a mechanical calculator with a sophisticated carry mechanism in 1642. After three years of effort and 50 prototypes he introduced his calculator to the public. He built twenty of these machines in the next ten years. This machine can add and subtract two numbers directly and multiply and divide by repetition. Because, unlike Schickard machines, Pascaline calls can only rotate in one direction that shoots it after each calculation requires the operator to make calls at all 9 and then (the re-zeroing method) multiplies the carry through the machine. This shows that the carry mechanism will prove itself in practice many times. This is a testament to the quality of Pascaline because there is no criticism of the 17th and 18th centuries that mentions a problem with carry mechanism and has not been fully tested on all machines, with reset, over time.

Pascal's discovery of a calculating machine, only three hundred years ago, was made when he was young at the age of nineteen. He was encouraged to do so by looking at the burden of arithmetic labor involved in his father's official duties as a tax inspector in Rouen. He contains the idea of ​​doing the work mechanically, and develops designs that are appropriate for this purpose; shows here the same combination of pure science and the mechanical genius that characterizes his entire life. But it is one thing to get pregnant and design the machine, and another to make it made and start to use. Here it takes a practical gift that he presents later in his invention...

In 1672, Gottfried Leibniz began work to add a direct doubling to what he understood as working Pascal's calculator. However, it is doubtful that he ever actually saw the mechanisms and methods could not succeed due to the lack of reversible rotation in the mechanism. Thus, he ends up designing an entirely new engine called Stepped Reckoner; using its Leibniz wheel, is the first two-motion calculator, the first using a cursor (creating the first operand memory) and the first having a movable carriage. Leibniz built two Stepped Reckoners, one in 1694 and one in 1706. Only a machine built in 1694 is known to exist; it was rediscovered at the end of the 19th century which has been forgotten in the attic at the University of GÃÆ'¶ttingen.

In 1893, the inventor of the German arithmetic machine, Arthur Burkhardt was asked to put the Leibniz machine in operating condition if possible. The report is profitable except for the order in carry.

Leibniz has invented the wheel of his name and the principle of two motion calculators, but after forty years of development, he can not produce a fully operational engine; this made Pascal's calculator the only mechanical calculator that worked in the 17th century. Leibniz was also the first to describe the pinwheel calculator. He once said, "It is not fitting for great men to lose hours like slaves in computational work that can be safely left to others if the machine is used."

Other calculating machines

Schickard, Pascal, and Leibniz were inevitably inspired by the highly celebrated role of the clock in the seventeenth century. However, the simple application of interrelated gears is not sufficient for their purposes. Schickard introduced the use of a toothed "toothed" to allow carry to take place. Pascal corrected it with his well-known weighted sautoir. Leibniz goes even further in relation to the ability to use movable carts to multiply more efficiently, even at the expense of a fully functional transport mechanism.

... I am designing the third one that works with springs and that has a very simple design. This is one, as I have stated, that I use many times, hidden in the eyes of the infinite and still in operation. However, while always improving it, I find a reason to change the design...

When, a few years ago, I saw for the first time an instrument that, when taken, automatically recorded the number of steps by pedestrians, I realized that all arithmetic could be subjected to a kind of machine so that not only count but also addition and subtraction, multiplication and division can completed with a properly arranged machine easily, quickly, and with definite results

The principle of the clock (the input wheel and the display wheel added to the clock like mechanism) for the direct incoming counting machine can not be applied to create a fully effective compute engine without additional innovation with 17th century technological capabilities. because their teeth will be stuck when it must be moved some places along the accumulator. The only seventeenth-century counting clock that survives to this day does not have a wide carrier mechanism and therefore can not be called a fully effective mechanical calculator. A much more successful clock was built by Italian Giovanni Poleni in the 18th century and was a two-step counting clock (the numbers were first written and then processed). In 1623, Wilhelm Schickard, a professor of Hebrew and German Astronomy, designed the counting clock he had drawn on the two letters he wrote to Johannes Kepler. The first machine built by a professional was destroyed during its construction and Schickard abandoned his project in 1624. These images have appeared in numerous publications for centuries, beginning in 1718 with a copy of Kepler's letters by Michael Hansch, but in the year 1957 was presented for the first time as a long-lost mechanical calculator. Franz Hammer. The construction of the first replicas of the 1960s showed that Schickard machines had unfinished designs and hence wheels and springs were added to make it work. The use of this replica shows that a single gear, when used in the calculation clock, is an inadequate carrier mechanism. (see Pascal versus Schickard). This does not mean that such machines can not be used in practice, but when the operator is faced with a mechanism that rejects rotation, in the unusual circumstances of a carry required outside (say) 3 dial, it will need to "help" spread.

  • Around 1643, the French watchmaker from Rouen, after hearing Pascal's work, built what he claimed to be his own design calculation clock. Pascal fired all his employees and stopped developing his calculator as soon as he heard the news. Only after being convinced that his invention will be protected by the king's privilege that he restarts his activity. A careful examination of this calculation clock indicates that it is not working properly and Pascal calls it avorton (the fetus is canceled).
  • In 1659, Tito Livio Burattini of Italy built a machine with nine independent wheels, each wheel is paired with a smaller carrying wheel. At the end of the operation, the user must manually add each haul to the next digit or mentally add these numbers to create the final result.
  • In 1666, Samuel Morland invented a machine designed to increase the amount of money, but it was not an actual addition machine because the carry was added to a small carry wheel located above each digit and indirectly to the next digit. It's very similar to the Burattini machine. Morland also created a machine that doubles with discs that can be exchanged based on Napier bones. Together these two engines provide a capacity similar to Schickard's discovery, although it is doubtful that Morland had experienced Schickard's calculation hours.
  • In 1673, French watchmaker RenÃÆ'Â © Grillet is described in Curiositez mathÃÆ' Â © dieques de l'invention du Sr Grillet, horlogeur ÃÆ' Paris a calculating machine that would be more succinct than a Pascal calculator and can be restored for subtraction. The only two known Grillet engines do not have a carry mechanism, featuring three lines of nine independent calls they also have nine rotating napier rods for multiplication and division. Contrary to Grillet's statement, it is not a mechanical calculator.

  • Facit TK Mechanical Calculator Demo (1936) - YouTube
    src: i.ytimg.com

    18th century

    Overview

    The 18th century saw the first mechanical calculator that could perform multiplication automatically; designed and built by Giovanni Poleni in 1709 and made of wood, it was the first successful counting clock. For all machines built in this century, the division still requires operators to decide when to stop repeated reductions on each index, and therefore these machines only provide help in dividing, such as the abacus. Both the pinwheel calculator and the Leibniz wheel calculator were built with some unsuccessful attempts in their commercialization.

    Prototype and running limited

    • In 1709, Giovanni Poleni of Italy was the first to make a calculator that could be automatically duplicated. It uses pinwheel design, is the first operational clock and is made of wood; he destroyed it after hearing that Antonius Braun had received 10,000 Guldens for dedicating his own design pinwheel machine to the Emperor Charles VI of Vienna.
    • In 1725, the French Academy of Sciences certified a calculating machine derived from a Pascal calculator designed by LÃÆ' Â © pine, a French craftsman. It was a bridge between Pascal's calculator and calculation clock. Transmission carriers are carried out simultaneously, as in the clock calculation, and therefore "the engine must be jammed outside some simultaneous carrier transmissions".
    • In 1727, a German, Antonius Braun, presented the first fully functioning two operating machines for Charles VI, Holy Roman Emperor in Vienna. Its shape is cylindrical and made of steel, silver and brass; it was finely decorated and looked like clock table renaisans. His dedication to the emperor engraved on the top of the machine also reads ".. to make fools easy, addition, subtraction, multiplication and even division".
    • In 1730, the French Academy of Sciences certified three machines designed by Hillerin de Boistissandeau. The first uses a single-gear mechanism which, according to Boistissandeau, will not work properly if a bag has to be moved more than two places; two other machines use springs that are gradually armed until they release their energy when a bag has to be moved forward. It's similar to a Pascal calculator but instead of using gravity energy, Boistissandeau uses the energy stored into the spring.
    • In 1770, Philipp MatthÃÆ'¤us Hahn, a German priest, built two circular calculating machines based on the Leibniz cylinder. J. C. Schuster, Hahn's brother-in-law, built some of Hahn's design machinery into the early 19th century.
    • In 1775, Lord Stanhope of Great Britain designed the pinwheel machine. It's arranged in a rectangular box with a handle on the side. He also designed the machine using a Leibniz wheel in 1777. "In 1777 Stanhope produced a Logic Demonstrator, a machine designed to solve problems in formal logic, marking the beginning of a new approach to the solution of a logical problem by the method mechanical. "
    • In 1784, Johann-Helfrich MÃÆ'¼ller built a machine very similar to Hahn's machine.

    Inside the Facit TK Mechanical Calculator - YouTube
    src: i.ytimg.com


    19th century

    Overview

    Luigi Torchi invented the first direct multiplication machine in 1834. It is also the second major driving force in the world, following James White (1822).

    Industrial mechanical calculator started in 1851 Thomas de Colmar released the simplified ArithmomÃÆ'¨tre which is the first machine that can be used every day in the office environment.

    For 40 years, the arithmometer is the only mechanical calculator available for sale and sold worldwide. By that time, in 1890, about 2,500 arithmometers had been sold plus several hundred more from two licensed clone arithmometer makers (Burkhardt, Germany, 1878 and Layton, UK, 1883). Felt and Tarrant, the only other competitor in actual commercial production, have sold 100 comptometers in three years.

    The cash register, created by American saloonkeeper James Ritty in 1879, addresses the old problem of irregularity and dishonesty in business transactions. It is a pure summing machine combined with a printer, bell and a two-sided screen that shows the paying party and the shopkeeper, if he wants, the amount of money exchanged for the current transaction.

    Cashier machines are easy to use and, unlike the original mechanical calculators, are needed and quickly adopted by so many businesses. "Eighty-four companies sold cash registers between 1888 and 1895, only three survived for a long time".

    In 1890, 6 years after John Patterson started the NCR Corporation, 20,000 machines had been sold by his own company against a total of around 3,500 for all of the original combined calculators.

    By 1900, NCR had built 200,000 cash registers and there were more companies producing them, compared to the "Thomas/Payen" arithmometer company that had just sold around 3,300 and Burroughs only sold 1,400 machines.

    Prototype and running limited

    • In 1820, Thomas de Colmar patented the Arithmometer. This is a true four-operation machine with a single digit/divider multiplier (the millionaire calculator released 70 years later has a similar user interface). He spent the next 30 years and 300,000 Franc developed his machine. This design was replaced in 1851 by a simple arithometer which is only an additional machine.
    • From 1840, Didier Roth patented and built several calculating machines, one of which is directly from Pascal's calculator.
    • In 1842, Timoleon Maurel discovered Arithmaurel, based on the Arithmometer, which could multiply two numbers by inserting their values ​​into the machine.
    • In 1845, Izrael Abraham Staffel first showed off machines that could add, subtract, divide, multiply, and gain square roots.
    • Around 1854, Andre-Michel Guerry invented Statistics Ordonnateur, a cylindrical tool designed to help summarize the relationship between data on moral variables (crime, suicide, etc.)
    • In 1872, Frank S. Baldwin in the U.S. create a pinwheel calculator.
    • In 1877 George B. Grant of Boston, MA, began producing Grant's mechanical counters capable of adding, subtraction, multiplication and division. The machine is 13x5x7 inches and contains eight pieces of workpiece made of brass and tempered steel. It was first introduced to the public at the 1876 Centennial Exhibition in Philadelphia.
    • In 1883, Edmondson of England patented a circular threaded drum machine

    Mechanical calculator made by Lawrence Hargrave - MAAS Collection
    src: d3ecqbn6etsqar.cloudfront.net


    1900s to 1970s

    The mechanical calculator reaches its peak

    Two different classes of mechanisms have been formed today, reciprocally and rotate. Former types of mechanisms operated usually by crank hand travel is limited; some detailed internal operations occur on the pull, and the other at the complete cycle release section. The machine illustrated in 1914 is of this type; the crank is vertical, on the right side. Then, some of these mechanisms are operated by electric motors and reduction gears that operate the crank and connect the rod to turn rotary motions into reciprocity.

    The latter, type, rotate, has at least one main axis that makes one [or more] continuous revolutions [s], one additional or subtraction per turn. Many designs, especially European calculators, have handcranks, and keys to ensure that the crank is restored to the right position after the turn is complete.

    The first half of the 20th century saw the gradual development of mechanical calculator mechanisms.

    The Dalton printing machine introduced in 1902 was the first of its kind to use only ten keys, and became the first of many "10-key additional" models produced by many companies.

    In 1948 the cylindrical Curta calculator, which was compact enough to be held in one hand, was introduced after being developed by Curt Herzstark in 1938. This is an extreme development of the stepping-gear calculation mechanism. This is reduced by adding a complement; between teeth for addition is the gear for reduction.

    From the early 1900s to the 1960s, mechanical calculators dominated the desktop computer market. Major suppliers in the US include Friden, Monroe, and SCM/Marchant. These tools are driven by motors, and have movable carriages in which the results of the calculations are displayed quickly. Almost all keyboards are full - each insertable digit has its own column with nine keys, 1..9, plus column-blank key, allowing multiple digit entries at once. (See the illustration below from Figurematic Marchant.) One could call this parallel entry, in contrast to the usual ten-key serial entry in mechanical adding machines, and now universal in electronic calculators. (Almost all Friden calculators, as well as some rotari (Germany) Diehls have a ten-key additional keyboard to include multipliers when multiplication.) Full keyboards generally have ten columns, though some low cost machines have eight. Most machines made by the three companies mentioned do not print their results, although other companies, such as Olivetti, do make a printing calculator.

    In this machine, the addition and subtraction are performed in one operation, as in a conventional mixing machine, but multiplication and division are achieved by the addition and subtraction of repetitive mechanics. Fridges make calculators that also provide square roots, essentially by dividing, but with additional mechanisms that automatically digitize numbers on the keyboard systematically. The last mechanical calculator tends to have a multiplication of shortcuts, and some ten keys, the entry-serial type has a decimal-point lock. However, the decimal-point lock requires significant additional significant internal complexity, and is only offered in the last design to be created. Hand-held mechanical calculators such as Curta 1948 continued to be used until they were displaced by electronic calculators in the 1970s.

    A typical European four operating machine uses the Odhner mechanism, or a variation of it. Such machines include Odhner Asli , Brunsviga and some of the following imitators, from Triumphator, Thales, Walther, Facit to Toshiba. Although most are operated by handcranks, there are motor-driven versions. Hamann's calculator is externally similar to the windmill engines, but the adjustment lever positions the cam that releases the pawl drive when the dial has moved quite far.

    Although Dalton was introduced in 1902 the first ten key printing adds (two operations, the other is reduction) of the machine, this feature is not in the computing (four operations) of the machine for many decades. Facit-T (1932) is the first 10-key computing machine to be sold in large quantities. Olivetti Divisumma-14 (1948) was the first computing machine with a 10-key printer and keyboard.

    The full keyboard engine, including motor-driven, was also built until the 1960s. Among the major manufacturers are Mercedes-Euclid, Archimedes, and MADAS in Europe; in the United States, Fridays, Marchant, and Monroe are major makers of swivel calculators with carriages. Reciprocating Calculators (mostly adding machines, many with integral printers) created by Remington Rand and Burroughs, among others. All of these are key-sets. Feel & amp; Tarrant makes Comptometers, as well as Victor, who is controlled by a key.

    The basic mechanism of Friden and Monroe is the modified Leibniz wheel (better known, perhaps informally, in the United States as a "stepped drum" or "stepping cast"). The Friden has a basic reversing drive between the engine body and the accumulator dial, so its main shaft always rotates in the same direction. MADAS Switzerland is similar. Monroe, however, reversed the direction of the main axle to be reduced.

    The earliest Marchants are pinwheel machines, but most of them are very sophisticated rotary types. They ran at 1,300 additional cycles per minute if [] bars were held. Others are limited to 600 cycles per minute, because the accumulator dial starts and stops for each cycle; Marchant calls are moving at constant and proportional speed for a continuous cycle. Most Marchants have a row of nine keys on the extreme right, as shown in the Figurematic photo. This only makes the machine increase the number of cycles corresponding to the number on the key, and then shifts the carriage. Even adding nine cycles only takes a short time.

    In Marchant, near the beginning of the cycle, the accumulator dial moves down "inward", away from the openings on the cover. They use the gears on the inside of the machine, which rotate them at speeds proportional to the numbers given to them, with an additional movement (minus 10: 1) of the hopper made by the dial to their right. At the completion of the cycle, the call will be aligned like a pointer in a traditional watt-hour meter. However, when they get out of the slope, a constant-lead disc adjusts them with a (limited-trip) spur gear differential. Also, bring a lower order added by another, planetary differential. (The machine shown has 39 differentials in the accumulator (20 digits)!)

    In any mechanical calculator, in essence, a tooth, a sector, or some similar device drives the accumulator with the number of teeth corresponding to the digit being added or subtracted - three teeth change position by a count of three. Most basic calculator mechanisms move the accumulator by starting, then moving at a constant speed, and stop. Specifically, stopping is very important, because to get the operation fast, accumulators need to move fast. The Geneva drive variant usually blocks the overshoot (which, of course, will create the wrong result).

    However, two different basic mechanisms, Mercedes-Euclid and Marchant, move quickly at speeds corresponding to added or reduced digits; a [1] drives the slowest accumulator, and [9], the fastest. In Mercedes-Euclide, a long-hollow lever, spinning at one end, moves nine shelves ("straight teeth") endwise at a distance proportional to the distance from the lever shaft. Each rack has a drive pin driven by a slot. The shelf for [1] is closest to the pivot, of course. For each digit of the keyboard, the slider selector wheel, like the one on the Leibniz wheel, involves a shelf corresponding to the digit entered. Of course, the accumulator changes either in forward or backward motions, but not both. This mechanism is very simple and relatively easy to create.

    The Marchant, however, has, for every one of the ten key columns, a nine-ratio "preselector" transmission with spur gear output at the top of the engine body; the gear hooks the accumulator gearing. When one tries to calculate the number of teeth in such transmission, the direct approach leads one to consider such mechanisms in the mechanical gas pump registers, which are used to denote the total price. However, this mechanism is very large, and completely impractical for a calculator; 90 tooth teeth tend to be found at gas stations. Practical gears in computing parts of the calculator can not have 90 teeth. They will be too big, or too smooth.

    Given that nine ratios per column imply significant complexity, a Marchant contains several hundred individual gears at all, much in the accumulator. Basically, the accumulator dial must rotate 36 degrees (1/10 turn) for [1], and 324 degrees (9/10 turn) for [9], not allowing to bring in. At some point in the tooth, one tooth must pass for [1], and nine teeth for [9]. There is no way to develop the required movement of the driveshaft which rotates one revolution per cycle with some teeth having a practical (relatively small) tooth.

    The Marchant, therefore, has three driveshafts to feed a small transmission. For one cycle, they rotate 1/2, 1/4, and 1/12 revolutions. [2]. 1/2-turn rotary shaft (for each column) gear with 12, 14, 16, and 18 gears, corresponding to the numbers 6, 7, 8, and 9. The shaft of a 1/4-turn (also, each column) with 12, 16, and 20 teeth, for 3, 4, and 5. Digits [1] and [2] are handled by 12 and 24 gears on a 1/12-revolution axis. The practical design puts the rev-12. axis further, so that the 1/4-spin axle brings 24-gear 24-gear drive of a free-spinning gear. For reductions, reversed driveshafts.

    At the beginning of the cycle, one of the five pendants moves outside the center to engage the appropriate gear for the selected digit.

    Some machines have as many as 20 columns in their full keyboard. The monsters in this field are Duodecillion created by Burroughs for exhibition purposes.

    For sterling currencies, Ã, Â £/s/d (and even farthings), there is a variety of basic mechanisms, especially with the number of different gear teeth and dial accumulator positions. To accommodate shilling and pence, additional columns are added for tens digits [10], 10 and 20 for shilling, and 10 for pence. Of course, this serves as a radix-20 and radix-12 mechanism.

    The variant of Marchant, called Binary-Octal Marchant, is a radix-8 (octal) machine. It was sold to inspect the early vacuum-tube (valve) computer for accuracy. (At that time, the mechanical calculator was much more reliable than a tube/valve computer.)

    In addition, there is a Marchant twin, consisting of two Marchant pinwheels with a common crank drive and an upside-down gearbox. [3] The twin engines are relatively rare, and appear to be used for survey calculations. At least one triple machine is made.

    Facit calculator, and the like, is basically a pinwheel machine, but a series of wheel wheels are moving sideways, not carriages. Pinwheel is a biquary; the numbers 1 to 4 cause the number of appropriate sliding pins to extend from the surface; digit 5 ​​â € <â €

    The buttons operate cams that operate the swinging lever to unlock the first cam pin-positioning which is part of the pinwheel mechanism; Further movement of the lever (with the number determined by the cam lock) rotates the pin-cam position to extend the number of pins required. [4]

    Stylus operated operators with circular slots for the stylus, and side-to-side wheels, such as those made by Sterling Plastics (AS), have an ingenious anti-overshoot mechanism to ensure accurate movement.

    End of era

    Source of the article : Wikipedia

    Comments
    0 Comments