Watch

2007 Schools Wikipedia Selection. Related subjects: Engineering

In naval parlance, watches are a timekeeping convention. The term in general use can mean any period of duty or responsibility, such as a hurricane watch.

A watch is a small portable timepiece or clock that displays the time and sometimes the day, date, month and year. In past centuries, these often took the form of pocket watches, which today are seldom carried or worn. In modern usage, watch is usually a contraction of wristwatch, a designation for the most popular style of timekeeping device worn on the wrist.

Because most watches lack a striking mechanism, such as a bell or gong to announce the passage of time, they are properly designated as timepieces, rather than clocks.

Overview

Today, the most common type of watch is the wristwatch, worn on the wrist and fastened with a watch strap or watchband, a bracelet made of real or synthetic leather, metal, nylon, or even ceramic. Before the inexpensive miniaturization that became possible in the 20th century, most watches were pocket watches, which had covers and were carried separately, often in a pocket and attached to a watch chain.

Most inexpensive and medium-priced watches used mainly for timekeeping are electronic watches with quartz movements, powered by electricity. Expensive, collectible watches valued more for their workmanship and aesthetic appeal than for simple timekeeping often have purely mechanical movements and are powered by springs, even though mechanical movements are many times less accurate than quartz movements. The most accurate watches have radio-controlled movements that are miniaturized, portable versions of radio clocks (q.v.).

Watch cases

Pocket timepieces

The earliest need for portability in timekeeping was navigation and mapping in the 15th century. The latitude could be measured by looking at the stars, but the only way a ship could measure its longitude was by comparing the midday (high noon) time of the local longitude to that of a European meridian (usually Paris or Greenwich)—a time kept on a shipboard clock. However, the process was notoriously unreliable until the introduction of John Harrison's chronometer. For that reason, most maps from the 15th century through the 19th century have precise latitudes but distorted longitudes.

The first reasonably accurate mechanical clocks measured time with weighted pendulums, which are useless at sea or in watches. The invention of a spring mechanism was crucial for portable clocks. In Tudor England, the development of “pocket-clockes” was enabled through the development of reliable springs and escapement mechanisms, which allowed clockmakers to compress a timekeeping device into a small, portable compartment.

In 1524, Peter Henlein created the first pocket watch. It is rumoured that Henry VIII (the portrait of Henry VIII at this link shows the medallion thought to be the back of his watch) had a pocket clock which he kept on a chain around his neck. However, these watches only had an hour hand—a minute hand would have been useless considering the inaccuracy of the watch mechanism. Eventually, miniaturization of these spring-based designs allowed for accurate portable timepieces which worked well even at sea.

In 1850, Aaron Lufkin Dennison founded Waltham Watch Company, which was the pioneer of the industrial manufacturing of pocket watches with interchangeable parts, the American System of Watch Manufacturing.

Breguet developed the first self-winding watch known as the perpetuelle in 1780[From the Breguet History Book].

Wristwatches

The wristwatch was invented by Patek Philippe at the end of the 19th century. At the time, it was considered a woman's accessory. It was not until the beginning of the 20th century that the Franco-Brazilian inventor Alberto Santos-Dumont, who had difficulty checking the time while in his first aircraft (Dumont was working on the invention of the aeroplane), asked his friend Louis Cartier for a watch he could use more easily. Cartier gave him a leather-band wristwatch from which Dumont never separated. Being a popular figure in Paris, Cartier was soon able to sell these watches to other men. During the First World War, officers in all armies soon discovered that in battlefield situations, quickly glancing at a watch on their wrist was far more convenient than fumbling in their jacket pockets for an old-fashioned pocket watch. In addition, as increasing numbers of officers were killed in the early stages of the war, NCOs promoted to replace them often did not have pocket watches (traditionally a middle-class item out of the reach of ordinary working-class soldiers), and so relied on the army to provide them with timekeepers. As the scale of battles increased, artillery and infantry officers were required to synchronize watches in order to conduct attacks at precise moments, whilst artillery officers were in need of a large number of accurate timekeepers for rangefinding and gunnery. Army contractors began to issue reliable, cheap, mass-produced wristwatches which were ideal for these purposes. When the war ended, demobilized European and American officers were allowed to keep their wristwatches, helping to popularize the items amongst middle-class Western civilian culture.

Today, many Westerners wear watches on their wrists, a direct result of World War I. The trend has since spread to other parts of the world, wherever accurate and convenient time references are required.

Watch movements

A movement in watchmaking is the mechanism that measures the passage of time and displays the current time (and possibly other information including date, month, day et cetera) to the wearer of the watch. Movements may be entirely mechanical, entirely electronic (potentially with no moving parts), or a blend of the two. Most watches intended mainly for timekeeping today have electronic movements, with mechanical hands on the face of the watch indicating the time.

Mechanical movements

Purely mechanical watches are still popular, although they are most commonly seen among expensive, collectible watches. The best of these are among the most precisely engineered mechanisms in existence, and this superb craftsmanship accounts for much of the attraction of purely mechanical watches.

Compared to electronic movements, mechanical watches keep very poor time, often with errors of seconds per day. They are frequently sensitive to position and temperature, they are costly to produce, they require regular maintenance and adjustment, and they are more prone to failure. For this reason, inexpensive and moderately priced timepieces with electronic movements now provide most users with superbly accurate timekeeping and have almost entirely supplanted older watch designs with mechanical movements.

Tuning-fork movements

Tuning fork watches (introduced by Bulova in 1960) use a 360 hertz tuning fork to drive a mechanical watch. Since the fork is used in place of a typical balance wheel, these watches naturally hum instead of ticking.

The inventor, Max Hetzel, was born in Basel, Switzerland, and joined the Bulova Watch Company of Bienne, Switzerland, in 1948. Hetzel was the first to use an electronic device, a transistor, in a wristwatch. Thus, he developed the first watch that could be qualified as electronic. However, fork movements are actually more "electrical", like an old electrical wall clock, than electronic. The sweep second hand moves fluidly like that of an old electrical wall clock.

Such watches were also sold by Swiss watch companies under license of Bulova. In 1974, after leaving Bulova, Hetzel developed a different tuning fork drive for Omega Watches. The watch featured a cal. 1220 micromotor, and a tuning fork frequency of 720 hertz. This development was obsolete compared to the newer electronic quartz watch which had become cheaper to produce and even more accurate.

Tuning fork movements are electromechanical. The task of converting electronically pulsed fork vibration into rotary movement is done via two tiny jeweled fingers that are connected to one of the tuning fork's tines. As the fork vibrates, the jeweled fingers precisely ratchet a tiny index wheel. This index wheel has over 300 barely visible teeth and spins more than 38 million times per year. The tiny electric coils that drive the tuning fork have 8000 turns of insulated copper wire with a diameter of 0.015 mm and a length of 90 meters. This amazing feat of engineering was prototyped in the 1950s.

Electronic movements

Electronic movements have few or no moving parts. Essentially, all modern electronic movements use the piezoelectric effect in a tiny quartz crystal to provide a stable time base for a mostly electronic movement: the crystal resonates at a specific, highly stable frequency that can be used to accurately pace a timekeeping mechanism. For this reason, electronic watches are often called quartz watches. Most quartz movements are primarily electronic but are geared to drive mechanical hands on the face of the watch in order to provide a traditional analog display of the time, which is still preferred by most consumers.

The first prototypes of electronic quartz watches were made by the CEH research laboratory in Switzerland in 1962. The first quartz watch to enter production was the Seiko 35 SQ Astron, which appeared in 1969. Modern quartz movements are produced in very large quantities, and even the cheapest wristwatches typically have quartz movements.

The best quartz movements are significantly more accurate than the worst, but the difference is much smaller than that found between mechanical movements and quartz movements. Quartz movements, even in their most inexpensive forms, are an order of magnitude more accurate than purely mechanical movements. Whereas mechanical movements can typically be off by several seconds a day, an inexpensive quartz movement in a child's wristwatch may still be accurate to within 500 milliseconds per day—ten times better than a mechanical movement.

Radio-controlled movements

Some electronic quartz watches are able to synchronize themselves with an external time source. These sources include radio time signals directly driven by atomic clocks, time signals from GPS navigation satellites, and others. These watches are free-running most of the time, but periodically align themselves with the chosen external time source automatically, typically once a day.

Because these watches are regulated by an external time source of extraordinarily high accuracy, they are never off by more than a small fraction of a second a day (depending on the quality of their quartz movements), as long as they can receive the external time signals that they expect. Additionally, their long-term accuracy is comparable to that of the external time signals they receive, which in most cases (such as GPS signals and special radio transmissions of time based on atomic clocks) is better than one second in three million years. For all practical purposes, then, radio-controlled wristwatches keep perfect time.

Movements of this type synchronize not only the time of day but also the date, the leap-year status of the current year, and the current state of daylight saving time (on or off). They obtain all of this information from the external signals that they receive. Because of this continual automatic updating, they never require manual setting or resetting.

A disadvantage of radio-controlled movements is that they cannot synchronize if radio reception conditions are poor. Even in this case, however, they will simply run autonomously with the same accuracy as a normal quartz watch until they are next able to synchronize.

Displaying the time

There are two main ways in which watches display the time to their owners: analog and digital.

Analog display

Traditionally, watches have displayed the time in analog form, with a numbered dial upon which are mounted at least a rotating hour hand and a longer, rotating minute hand. Many watches also incorporate a third hand that shows the current second of the current minute. Watches powered by quartz have second hands that snap every second to the next marker. Watches powered by a mechanical movement have a "sweeping second hand", the name deriving from its uninterrupted smooth (sweeping) movement across the markers. All of the hands are normally mechanical, physically rotating on the dial, although a few watches have been produced with “hands” that are simulated by a liquid-crystal display.

Analog display of the time is nearly universal in watches sold as jewelry or collectibles, and in these watches, the range of different styles of hands, numbers, and other aspects of the analog dial is very broad. In watches sold for timekeeping, analog display remains very popular, as many people find it easier to read than digital display; but in timekeeping watches the emphasis is on clarity and accurate reading of the time under all conditions (clearly marked digits, easily visible hands, large watch faces, etc.).

Digital display

Since the advent of electronic watches that incorporate small computers, digital displays have also been available. A digital display simply shows the time as a number, e.g., 10:30 AM instead of a short hand pointing towards the number 10 and a long hand pointing towards the number 6 on a dial.

Cheaper electronics permitted the popularization of the digital watch in the second half of the 20th century. They were seen as the great new thing. Douglas Adams, in the introduction of his novel The Hitchhiker's Guide to the Galaxy, would say that humans were "so amazingly primitive that they still think digital watches are a pretty neat idea."

The first digital watch, a Pulsar prototype in 1970, was developed jointly by Hamilton Watch Company and Electro-Data. A retail version of the Pulsar was put on sale on April 4th 1972. It had a red light-emitting diode (LED) display. Another early digital watch innovator, Roger Riehl's Synchronar Mark 1, provided an LED display and used solar cells to power the internal nicad batteries. Most watches with LED displays required that the user press a button to see the time displayed for a few seconds, because LEDs used so much power that they could not be kept operating continuously. Watches with LED displays were popular for the next few years, but soon the LED displays were superseded by liquid crystal displays (LCDs), which used less battery power. The first LCD watch with a six-digit LCD was the 1973 Seiko 06LC, although various forms of early LCD watches with a four-digit display were marketed as early as 1972 including the 1972 Gruen Teletime LCD Watch.

Digital watches did not replace analog watches. In fact, after a number of years of great popularity, digital watches fell somewhat out of fashion, and today most watches display the time in analog form, with mechanical hands, even if all the internal parts of the watch are electronic.

Almost all watches with digital displays today are in the category of simple timekeeping watches, and they are particularly popular with “geek watches” that incorporate a very large number of features besides simply showing the date and time. Watches sold as jewelry or collectibles almost never have digital displays.

Expensive watches for collectors rarely have digital displays due to there being little demand for them. Less craftsmanship is required to make a digital face of a watch and most collectors find that analog dials (especially with complications)vary in quality more than digital dials due to the details and finishing of the parts that make up the dial (thus making the differences between a cheap and expensive watch more evident).

Watch functions

All watches provide the time of day, giving at least the hour and minute, and usually the second. Most also provide the current date, and often the day of the week as well. However, many watches also provide a great deal of information beyond the basics of time and date.

Some elaborate and more expensive watches, both pocket and wrist models, also incorporate striking mechanisms or repeater functions, so that the wearer could learn the time by the sound emanating from the watch. This announcement or striking feature is an essential characteristic of true clocks and distinguishes such watches from ordinary timepieces.

Complicated watches

A complicated watch has one or more functionalities beyond the basic function of displaying the time and the date; such a functionality is called a complication. Two popular complications are the chronograph complication, which is the ability of the watch movement to function as a stopwatch, and the moonphase complication, which is a display of the lunar phase. Among watch enthusiasts, complicated watches are especially collectible.

Chronographs and chronometers

The similar-sounding terms chronograph and chronometer are often confused, although they mean altogether different things. A chronograph is a type of complication, as explained above. A chronometer is an all-mechanical watch or clock whose movement has been tested and certified to operate within a certain standard of accuracy by the COSC (Contrôle Officiel Suisse des Chronomètres). The concepts are different but not mutually exclusive; a watch can be a chronograph, a chronometer, both, or neither.

Fashionable watches

At the end of the 20th century, Swiss watch makers were seeing their sales go down as analog clocks were considered obsolete. They joined forces with designers from many countries to reinvent the Swiss watch.

The result was that they could considerably reduce the pieces and production time of an analog watch. In fact it was so cheap that if a watch broke it would be cheaper to throw it away and buy a new one than to repair it. They founded the Swiss Watch company ( Swatch) and called graphic designers to redesign a new annual collection.

This is often used as a case study in design schools to demonstrate the commercial potential of industrial and graphic design.

Collectible and jewelry watches

Wristwatches are often treated as jewelry or as collectible works of art rather than as timepieces. This has created several different markets for wristwatches, ranging from very inexpensive but accurate watches intended for no other purpose than telling the correct time, to extremely expensive watches that serve mainly as personal adornment or as examples of high achievement in miniaturization and precision mechanical engineering, without any pretense at being accurate for telling the time. Still another market is that of “geek watches”—watches that not only tell the time, but incorporate computers, satellite navigation, complications of various orders, and many other features that may be quite removed from the basic concept of timekeeping.

Most companies that produce watches specialize in one of these markets. Companies such as Rolex or Chopard specialize in watches as jewelry or fine mechanical devices. Companies such as Casio specialize in watches as timepieces or multifunctional computers. Since watches are considered by many to be both functional and attractive, there are many types and manufacturers to choose from.

Important collectible American made watches from the early 20th Century were the best available at any price. Leading watchmakers included Elgin, Gruen, Hamilton, and Illinois. Hamilton is generally considered as having the finest early American movements, while the art deco styling of The Illinois Watch Company was unsurpassed worldwide. Early Gruen Curvex models remain very desired for how they entwined form and function, and Elgin made more watches than anyone else.

Advanced watches

Many technological enhancements to wristwatches have been explored but most of them remained unnoticed. In 2005 for example, one company marketed an alarm wristwatch with an accelerometer inside that monitors the user's sleep and rings during one of his almost-awake phases.

A number of functionalities not directly related to time have also been inserted into watches. As miniaturized electronics became cheaper, watches have been developed containing calculators, video games, digital cameras, keydrives, GPS receivers and cellular phones. In the early 1980s Seiko marketed a watch with a television receiver in it, although at the time television receivers were too bulky to fit in a wristwatch, and the actual receiver and its power source were in a book-sized box with a cable that ran to the wristwatch. In the early 2000s, a self-contained wristwatch television receiver came on the market, with a strong enough power source to provide one hour of viewing.

These watches have not had sustained long-term sales success. As well as awkward user interfaces due to the tiny screens and buttons possible in a wearable package, and in some cases short battery life, the functionality available has not generally proven sufficiently compelling to attract buyers. Such watches have also had the reputation as ugly and thus mainly geek toys. Now with the ubiquity of the mobile phone in many countries, which have bigger screens, buttons, and batteries, interest in incorporating extra functionality in watches seems to have declined.

Several companies have however attempted to develop a computer contained in a wristwatch (see also wearable computer). As of 2005, the only programmable computer watches to have made it to market are the Seiko Ruputer, the Matsucom onHand, and the Fossil, Inc. Wrist PDA, although many digital watches come with extremely sophisticated data management software built in.

Spacewatches

Zero gravity environment and other extreme conditions encountered by astronauts in deep space requires the use of specially tested watches. During the 60s, a large range of watches were tested for durability and precision under extreme temperature changes and vibrations. The Omega Speedmaster was selected by both Soviet and US space agencies.

The Breitling Navitimer Cosmonaute was designed with a 24-hour dial to avoid confusion between AM and PM, which are meaningless in space. It was first worn in space by astronaut Scott Carpenter on May 24th, 1962 in the Aurora 7 capsule.

More recently, Soviet and Russian cosmonauts have used the Fortis B-42.

Chinese taikonauts wear the Fiyta spacewatches.

Mobile phones as pocket watches

In the early 2000s, the carrying of mobile telephones has become ubiquitous in many affluent and even some developing countries. As these phones typically display the time on their screens when not in use, it has become common to rely on them for time-keeping, effectively making the mobile phone serve the function of a pocket watch.