Watch Movement

A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet, including metal bands, leather straps or any other kind of bracelet. A pocket watch is designed for a person to carry in a pocket, often attached to a chain.

Watches were developed in the 17th century from spring-powered clocks, which appeared as early as the 14th century. During most of its history the watch was a mechanical device, driven by clockwork, powered by winding a mainspring, and keeping time with an oscillating balance wheel. These are called ''mechanical watches''. In the 1960s the electronic ''quartz watch'' was invented, which was powered by a battery and kept time with a vibrating quartz crystal. By the 1980s the quartz watch had taken over most of the market from the mechanical watch. Historically, this is called the quartz revolution (also known as quartz crisis in Switzerland). Developments in the 2010s include ''smartwatches'', which are elaborate computer-like electronic devices designed to be worn on a wrist. They generally incorporate timekeeping functions, but these are only a small subset of the smartwatch's facilities.

In general, modern watches often display the day, date, month, and year. For mechanical watches, various extra features called " complications," such as moon-phase displays and the different types of tourbillon, are sometimes included. Most electronic quartz watches, on the other hand, include time-related features such as timers, chronographs and alarm functions. Furthermore, some modern watches (like smartwatches) even incorporate calculators, GPS and Bluetooth technology or have heart-rate monitoring capabilities, and some of them use radio clock technology to regularly correct the time.

Most watches that are used mainly for timekeeping have quartz movements. However, expensive collectible watches, valued more for their elaborate craftsmanship, aesthetic appeal, and glamorous design than for simple timekeeping, often have traditional mechanical movements, despite being less accurate and more expensive than their electronic counterparts. As of 2018, the most expensive watch ever sold at auction was the Patek Philippe Henry Graves Supercomplication, the world's most complicated mechanical watch until 1989, fetching US$24 million ( CHF 23,237,000) in Geneva on 11 November 2014. As of December 2019, the most expensive watch ever sold at auction (and wristwatch) was the Patek Philippe Grandmaster Chime Ref. 6300A-010, fetching US$31.19 million (CHF 31,000,000) in Geneva on 9 November 2019.

History

Origins

Watches evolved from portable spring-driven clocks, which first appeared in 15th-century Europe. The first timepieces to be worn, made in the 16th century beginning in the German cities of Nuremberg and Augsburg, were transitional in size between clocks and watches. Nuremberg clockmaker Peter Henlein (or Henle or Hele) (1485-1542) is often credited as the inventor of the watch. However, other German clockmakers were creating miniature timepieces during this period, and there is no evidence Henlein was the first.

Watches were not widely worn in pockets until the 17th century. One account suggests that the word "watch" came from the Old English word ''woecce'' - which meant "watchman" – because town watchmen used the technology to keep track of their shifts at work. Another says that the term came from 17th-century sailors, who used the new mechanisms to time the length of their shipboard ''watches'' (duty shifts).

Evolution

A rise in accuracy occurred in 1657 with the addition of the balance spring to the balance wheel, an invention disputed both at the time and ever since between Robert Hooke and Christiaan Huygens. This innovation increased watches' accuracy enormously, reducing error from perhaps several hours per day to perhaps 10 minutes per day, resulting in the addition of the minute hand to the face from around 1680 in Britain and around 1700 in France.

The increased accuracy of the balance wheel focused attention on errors caused by other parts of the movement, igniting a two-century wave of watchmaking innovation. The first thing to be improved was the escapement. The verge escapement was replaced in quality watches by the cylinder escapement, invented by Thomas Tompion in 1695 and further developed by George Graham in the 1720s. Improvements in manufacturing – such as the tooth-cutting machine devised by Robert Hooke – allowed some increase in the volume of watch production, although finishing and assembling was still done by hand until well into the 19th century.

A major cause of error in balance-wheel timepieces, caused by changes in elasticity of the balance spring from temperature changes, was solved by the bimetallic temperature-compensated balance wheel invented in 1765 by Pierre Le Roy and improved by Thomas Earnshaw (1749–1829). The lever escapement, the single most important technological breakthrough, though invented by Thomas Mudge in 1759 and improved by Josiah Emery in 1785, only gradually came into use from about 1800 onwards, chiefly in Britain.

The British predominated in watch manufacture for much of the 17th and 18th centuries, but maintained a system of production that was geared towards high-quality products for the élite. The British Watch Company modernized clock manufacture with mass-production techniques and the application of duplicating tools and machinery in 1843. In the United States, Aaron Lufkin Dennison started a factory in 1851 in Massachusetts that used interchangeable parts, and by 1861 a successful enterprise operated, incorporated as the Waltham Watch Company.. Reprinted by McGraw-Hill, New York and London, 1926 (); and by Lindsay Publications, Inc., Bradley, Illinois, ().

Wristwatches

The concept of the wristwatch goes back to the production of the very earliest watches in the 16th century. In 1571 Elizabeth I of England received a wristwatch, described as an "armed watch," from Robert Dudley. The oldest surviving wristwatch (then described as a "bracelet watch") is one made in 1806 and given to Joséphine de Beauharnais. From the beginning, wristwatches were almost exclusively worn by women - men used pocket watches up until the early-20th century. In 1810, the watch-maker Abraham-Louis Breguet made a wristwatch for the Queen of Naples. The first Swiss wristwatch was made by the Swiss watch-maker Patek Philippe, in the year 1868 for Countess Koscowicz of Hungary.

Wristwatches were first worn by military men towards the end of the 19th century, having increasingly recognized the importance of synchronizing maneuvers during war without potentially revealing plans to the enemy through signaling. The Garstin Company of London patented a "Watch Wristlet" design in 1893, but probably produced similar designs from the 1880s. Officers in the British Army began using wristwatches during colonial military campaigns in the 1880s, such as during the Anglo-Burma War of 1885. During the First Boer War of 1880–1881 the importance of coordinating troop movements and synchronizing attacks against highly mobile Boer insurgents became paramount, and the use of wristwatches subsequently became widespread among the officer class. The company Mappin & Webb began production of their successful "campaign watch" for soldiers during the campaign in the Sudan in 1898 and accelerated production for the Second Boer War of 1899–1902 a few years later. In continental Europe, Girard-Perregaux and other Swiss watchmakers began supplying German naval officers with wristwatches in about 1880.

Early models were essentially standard pocket-watches fitted to a leather strap, but by the early 20th century, manufacturers began producing purpose-built wristwatches. The Swiss company Dimier Frères & Cie patented a wristwatch design with the now standard wire lugs in 1903.

In 1904, Louis Cartier produced a wristwatch to allow his friend Alberto Santos-Dumont to check flight performance in his airship while keeping both hands on the controls as this proved difficult with a pocket watch. Cartier still markets a line of Santos-Dumont watches and sunglasses.Cartier sunglasses
"Cartier rimmed sunglasses" (English).
cartier.com. Retrieved: 9 December 2012.

In 1905, Hans Wilsdorf moved to London and set up his own business, Wilsdorf & Davis, with his brother-in-law Alfred Davis, providing quality timepieces at affordable prices; the company became Rolex in 1915. Wilsdorf was an early convert to the wristwatch, and contracted the Swiss firm Aegler to produce a line of wristwatches.

The impact of the First World War of 1914–1918 dramatically shifted public perceptions on the propriety of the man's wristwatch and opened up a mass market in the postwar era. The creeping barrage artillery tactic, developed during the war, required precise synchronization between the artillery gunners and the infantry advancing behind the barrage. Service watches produced during the war were specially designed for the rigors of trench warfare, with luminous dials and unbreakable glass. The War Office began issuing wristwatches to combatants from 1917. By the end of the war, almost all enlisted men wore a wristwatch (or wristlet), and after they were demobilized the fashion soon caught on: the British ''Horological Journal'' wrote in 1917 that "the wristlet watch was little used by the sterner sex before the war, but now is seen on the wrist of nearly every man in uniform and of many men in civilian attire." By 1930, the wristwatch vastly exceeded the pocket watch in market share by a decisive ratio of 50:1.

Automatic watches

John Harwood invented the first successful self-winding system in 1923. In anticipation of Harwood's patent for self-winding mechanisms expiration in 1930, Glycine founder Eugène Meylan started development on a self-winding system as a separate module that could be used with almost any 8.75 ligne (19.74 millimeter) watch movement. Glycine incorporated this module into its watches in October 1930 and began mass-producing automatic watches.

Electric watches

The Elgin National Watch Company and the Hamilton Watch Company pioneered the first electric watch. The first electric movements used a battery as a power source to oscillate the balance wheel. During the 1950s Elgin developed the model 725 while Hamilton released two models: the first, the Hamilton 500, released on 3 January 1957, was produced into 1959. This model had problems with the contact wires misaligning, and the watches returned to Hamilton for alignment. The Hamilton 505, an improvement on the 500, proved more reliable: the contact wires were removed and a non-adjustable contact on the balance assembly delivered the power to the balance wheel. Similar designs from many other watch companies followed. Another type of electric watch was developed by the Bulova company that used a tuning-fork resonator instead of a traditional balance wheel to increase timekeeping accuracy, moving from a typical 2.5–4 Hz with a traditional balance wheel to 360 Hz with the tuning-fork design.

Quartz watches

The commercial introduction of the quartz watch in 1969 in the form of the Seiko Astron 35SQ and in 1970 in the form of the Omega Beta 21 was a revolutionary improvement in watch technology. In place of a balance wheel which oscillated at perhaps 5 or 6 beats per second, these devices used a quartz-crystal resonator which vibrated at 8,192 Hz, driven by a battery-powered oscillator circuit. Most quartz-watch oscillators now operate at 32,768 Hz, although quartz movements have been designed with frequencies as high as 262 kHz. Since the 1980s, more quartz watches than mechanical ones have been marketed.

Parts

The movement and case are the basic parts of a watch. A watch band or bracelet is added to form a wristwatch; alternatively, a watch chain is added to form a pocket watch.

The case is the outer covering of the watch.

The case back is the back portion of the watch's case. Accessing the movement (such as during battery replacement) depends on the type of case back, which are generally categorized into four types:
* Snap-off case backs (press-on case backs): the watch back pulls straight off and presses straight on.
* Screw-down case backs (threaded case backs): the entire watch back must be rotated to unscrew from the case. Often it has 6 notches on the external part of the case back.
* Screw back cases: tiny screws hold the case back to the case
* Unibody: the only way into the case involves prying the crystal off the front of the watch.

The crystal, also called the window or watch glass, is the transparent part of the case that allows viewing the hands and the dial of the movement.
Modern wristwatches almost always use one of 4 materials:
* Acrylic glass (plexiglass, hesalite glass): the most impact-resistant ("unbreakable"), and therefore used in dive watches and most military watches. Acrylic glass is the lowest cost of these materials, so it is used in practically all low-cost watches.
* Mineral crystal: a tempered glass.
* Sapphire-coated mineral crystal
* Synthetic sapphire crystal: the most scratch-resistant; it is difficult to cut and polish, causing watch crystals made of sapphire to be the most expensive.

The bezel is the ring holding the crystal in place.
Katelyn Fogle
"10 Parts of a Watch You Should Actually Know"

The lugs are small metal projections at both ends of the wristwatch case where the watch band attaches to the watch case.
The case and the lugs are often machined from one solid piece of stainless steel.

Movement

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

Mechanical

Compared to electronic movements, mechanical watches are less accurate, often with errors of seconds per day; are sensitive to position, temperature, and magnetism; are costly to produce; require regular maintenance and adjustments; and are more prone to failures. Nevertheless, mechanical watches attract interest from consumers, particularly among watch collectors. Skeleton watches are designed to display the mechanism for aesthetic purposes.

A mechanical movement uses an escapement mechanism to control and limit the unwinding and winding parts of a spring, converting what would otherwise be a simple unwinding into a controlled and periodic energy release. The movement also uses a balance wheel, together with the balance spring (also known as a hairspring), to control gear system's motion in a manner analogous to the pendulum of a pendulum clock. The tourbillon, an optional part for mechanical movements, is a rotating frame for the escapement, used to cancel out or reduce gravitational bias. Due to the complexity of designing a tourbillon, they are expensive, and typically found in prestigious watches.

The pin-lever escapement (called the Roskopf movement after its inventor, Georges Frederic Roskopf), which is a cheaper version of the fully levered movement, was manufactured in huge quantities by many Swiss manufacturers, as well as by Timex, until it was replaced by quartz movements.

Introduced by Bulova in 1960, tuning-fork watches use a type of electromechanical movement with a precise frequency (most often ) to drive a mechanical watch. The task of converting electronically pulsed fork vibration into rotary movements is done via two tiny jeweled fingers, called pawls. Tuning-fork watches were rendered obsolete when electronic quartz watches were developed.

Traditional mechanical watch movements use a spiral spring called a mainspring as its power source that must be rewound periodically by the user by turning the watch crown. Antique pocket watches were wound by inserting a key into the back of the watch and turning it. While most modern watches are designed to run on a winding, requiring winding daily, some run for several days; a few have 192-hour mainsprings, requiring once-weekly winding.

Automatic watches

A ''self-winding'' or ''automatic'' watch is one that rewinds the mainspring of a mechanical movement by the natural motions of the wearer's body. The first self-winding mechanism was invented for pocket watches in 1770 by Abraham-Louis Perrelet, but the first "self-winding," or "automatic," wristwatch was the invention of a British watch repairer named John Harwood in 1923. This type of watch winds itself without requiring any special action by the wearer. It uses an eccentric weight, called a winding rotor, which rotates with the movement of the wearer's wrist. The back-and-forth motion of the winding rotor couples to a ratchet to wind the mainspring automatically. Self-winding watches usually can also be wound manually to keep them running when not worn or if the wearer's wrist motions are inadequate to keep the watch wound.

In April 2014 the Swatch Group launched the ''sistem51'' wristwatch. It has a purely mechanical movement consisting of only 51 parts, including a novel self-winding mechanism with a transparent oscillating weight. So far, it is the only mechanical movement manufactured entirely on a fully automated assembly line. The low parts count and the automated assembly make it an inexpensive mechanical Swiss watch, which can be considered a successor to Roskopf movements, although of higher quality.

Electronic

Electronic movements, also known as quartz movements, have few or no moving parts, except a quartz crystal which is made to vibrate by the piezoelectric effect. A varying electric voltage is applied to the crystal, which responds by changing its shape so, in combination with some electronic components, it functions as an oscillator. It resonates at a specific highly stable frequency, which is used to accurately pace a timekeeping mechanism. Most quartz movements are primarily electronic but are geared to drive mechanical hands on the face of the watch to provide a traditional analog display of the time, a feature most consumers still prefer.

In 1959 Seiko placed an order with Epson (a subsidiary company of Seiko and the 'brain' behind the quartz revolution) to start developing a quartz wristwatch. The project was codenamed 59A. By the 1964 Tokyo Summer Olympics, Seiko had a working prototype of a portable quartz watch which was used as the time measurements throughout the event.

The first prototypes of an electronic quartz wristwatch (not just quartz watches as the Seiko timekeeping devices at the Tokyo Olympics in 1964) were made by the CEH research laboratory in Neuchâtel, Switzerland. From 1965 through 1967 pioneering development work was done on a miniaturized 8192 Hz quartz oscillator, a thermo-compensation module, and an in-house-made, dedicated integrated circuit (unlike the hybrid circuits used in the later Seiko Astron wristwatch). As a result, the BETA 1 prototype set new timekeeping performance records at the International Chronometric Competition held at the Observatory of Neuchâtel in 1967. In 1970, 18 manufacturers exhibited production versions of the beta 21 wristwatch, including the Omega Electroquartz as well as Patek Philippe, Rolex Oysterquartz and Piaget.

The first quartz watch to enter production was the Seiko 35 SQ Astron, which hit the shelves on 25 December 1969, swiftly followed by the Swiss Beta 21, and then a year later the prototype of one of the world's most accurate wristwatches to date: the Omega Marine Chronometer. Since the technology having been developed by contributions from Japanese, American and Swiss, nobody could patent the whole movement of the quartz wristwatch, thus allowing other manufacturers to participate in the rapid growth and development of the quartz watch market. This ended - in less than a decade - almost 100 years of dominance by the mechanical wristwatch legacy. Modern quartz movements are produced in very large quantities, and even the cheapest wristwatches typically have quartz 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 half a second per day - ten times more accurate than a mechanical movement.

After a consolidation of the mechanical watch industry in Switzerland during the 1970s, mass production of quartz wristwatches took off under the leadership of the Swatch Group of companies, a Swiss conglomerate with vertical control of the production of Swiss watches and related products. For quartz wristwatches, subsidiaries of Swatch manufacture watch batteries ( Renata), oscillators (Oscilloquartz, now Micro Crystal AG) and integrated circuits (Ebauches Electronic SA, renamed EM Microelectronic-Marin). The launch of the new SWATCH brand in 1983 was marked by bold new styling, design, and marketing. Today, the Swatch Group maintains its position as the world's largest watch company.

Seiko's efforts to combine the quartz and mechanical movements bore fruit after 20 years of research, leading to the introduction of the Seiko Spring Drive, first in a limited domestic market production in 1999 and to the world in September 2005. The Spring Drive keeps time within quartz standards without the use of a battery, using a traditional mechanical gear train powered by a spring, without the need for a balance wheel either.

In 2010, Miyota (Citizen Watch) of Japan introduced a newly developed movement that uses a 3-pronged quartz crystal that was exclusively produced for Bulova to be used in the Precisionist or Accutron II line, a new type of quartz watch with ultra-high frequency (262.144 kHz) which is claimed to be accurate to +/− 10 seconds a year and has a smooth sweeping second hand rather than one that jumps each second.

Radio time signal watches are a type of electronic quartz watch that synchronizes (time transfers) its time with an external time source such as in atomic clocks, time signals from GPS navigation satellites, the German DCF77 signal in Europe, WWVB in the US, and others. Movements of this type may - among others - synchronize the time of day and the date, the leap-year status and the state of daylight saving time (on or off). However, other than the radio receiver, these watches are normal quartz watches in all other aspects.

Electronic watches require electricity as a power source, and some mechanical movements and hybrid electronic-mechanical movements also require electricity. Usually, the electricity is provided by a replaceable battery. The first use of electrical power in watches was as a substitute for the mainspring, to remove the need for winding. The first electrically powered watch, the Hamilton Electric 500, was released in 1957 by the Hamilton Watch Company of Lancaster, Pennsylvania.

Watch batteries (strictly speaking cells, as a battery is composed of multiple cells) are specially designed for their purpose. They are very small and provide tiny amounts of power continuously for very long periods (several years or more). In most cases, replacing the battery requires a trip to a watch-repair shop or watch dealer; this is especially true for watches that are water-resistant, as special tools and procedures are required for the watch to remain water-resistant after battery replacement. Silver-oxide and lithium batteries are popular today; mercury batteries, formerly quite common, are no longer used, for environmental reasons. Cheap batteries may be alkaline, of the same size as silver-oxide cells but providing shorter life. Rechargeable batteries are used in some solar-powered watches.

Some electronic watches are powered by the movement of the wearer. For instance, Seiko's kinetic-powered quartz watches use the motion of the wearer's arm: turning a rotating weight which causes a tiny generator to supply power to charge a rechargeable battery that runs the watch. The concept is similar to that of self-winding spring movements, except that electrical power is generated instead of mechanical spring tension.

Solar powered watches are powered by light. A photovoltaic cell

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