What is the name of the mechanism in a watch? Watch escapement

The first mechanical watch.

First mentions of mechanical watch date back to the end of the 6th century. Most likely, it was a water clock, which had a built-in mechanical device to activate additional functions, for example, the combat mechanism.

True mechanical watches appeared in the 13th century in Europe. They were not yet reliable enough, so they had to constantly check the time using a sundial. Their clock mechanism worked using the energy of a descending load, which was used for a long time as stone weights. To start such a clock, one had to lift a very heavy weight to a considerable height.

It is worth noting that mechanical watches created in the 13th-14th centuries were very large and were used extremely rarely. They were installed only in monasteries so that the monks could get ready for services on time. It was the monks who decided to put 12 divisions on the circle, each of which corresponded to one hour. Only in the 16th century did clocks appear on city buildings.

In the XIV-XV centuries the first floor and Wall Clock. At first they were quite heavy, as they were driven by a weight that had to be tightened every 12 hours. Such clocks were made of iron, and a little later of brass, and their design was similar to that of a tower clock.

In the second half of the 15th century, the first watches with a spring motor were created. The source of energy in such watches was a steel spring, which, when unwinding, turned the wheels of the clock mechanism. The first table spring clock was made from bronze by an unknown craftsman. The height of this clock was half a meter.

The first portable spring clocks were made of brass and shaped like a round or square box. The dial of such a watch was horizontal. Convex brass balls were placed in a circle on it, which helped determine the time by touch in the dark. The arrow was made in the shape of a dragon or other mythical creature.

Science continued to develop, and along with it, mechanical watches improved. The first pocket watches appeared in the 16th century. Such devices were very rare, so only rich people could afford them. Very often, pocket watches were decorated with precious stones. But even then they continued to check the time using a sundial. Some watches even had two dials: mechanical on one side and solar on the other.

In 1657, Christiaan Huygens assembled a mechanical pendulum clock. They were distinguished by their extraordinary accuracy compared to all timekeeping instruments existing at that time. If before the advent of the pendulum, clocks that were slow or fast by 30 minutes per day were considered accurate, but now the error was no more than 3 minutes per week. In 1674, Huygens improved the regulator of the spring clock. His invention required the creation of a qualitatively new trigger mechanism. A little later this mechanism was invented. It became an anchor.

Huygens' inventions became widespread in many countries. Watchmaking began to actively develop. The clock error gradually decreased, and the mechanisms could be wound once every eight days.

Due to the increasing accuracy of watches, the first mechanisms with a minute hand were created in 1680. At the same time, a second row of numbers appeared on the dial plate to indicate minutes, using Arabic numerals. And in the middle of the 18th century, watches with a second hand appeared.

At this time, the Rococo style dominated in all types of art. In watchmaking, his influence was expressed in the variety of watch shapes and materials used, the abundance of carved patterns, scrolls, external decorations made of gold and precious stones. At the same time, carriage clocks came into fashion. It is believed that travel or carriage clocks appeared thanks to the French mechanic and watchmaker Abraham-Louis Breguet.

Most often they were rectangular in shape with glass side walls. A brass handle was attached to the top of the case, which served to carry the watch. All brass surfaces of the watch were plated with gold. It is worth noting that appearance Travel clocks remained virtually unchanged throughout the century.

Improvements to the clock mechanism in the second half of the 18th century made watches flatter and smaller in size. But, despite the changes in the appearance of watches, they still continued to remain the prerogative of a select few. Only in the second half of the 19th century they began to be produced in large quantities in Germany, England, the USA, and also Switzerland.

Mechanical watches have evolved for at least five centuries. Today they are conventionally divided not only by the type of clock mechanism (pendulum, balance, tuning fork, quartz, quantum), but also by purpose (household and special).

Household clocks include tower, wall, table, wrist and pocket clocks. Specialized watches are divided depending on their purpose. Among them you can find diving watches, signal watches, chess watches, antimagnetic watches, and many others. The prototype of modern mechanical watches is the pendulum clock of H. Huygens, created in 1657.

Plan:

1. History
- 1.1 Liquid trigger
- 1.2 Mechanical trigger
2 Reliability
3 Accuracy
4 Mechanical escapements
- 4.1 Pin trigger
- 4.2 Anchor release mechanism
- 4.3 Bestial trigger mechanism
- 4.4 Lever trigger
- 4.5 Duplex (two-way) trigger mechanism
- 4.6 Grasshopper trigger
- 4.7 Gravity trigger
5 Electromechanical escapements
- 5.1 Hipp Clock
- 5.2 Free pendulum clock

Introduction

The simplest watch escapement mechanism. A weight or spring rotates the gear, and with the help of the escapement mechanism it pushes the pendulum in one direction or the other.

Watch escapement(in watchmaker's language: descent, move) (fr. échappement, English escapement, German hemmung) - in a mechanical watch: a device that converts continuous rotational motion into oscillatory or reciprocating motion. This device ensures uniform expenditure of energy stored in a spring or weight.

The escapement moves the watch's oscillating element, usually a pendulum or balance wheel. It itself receives energy from a toothed gear, which is rotated by a spiral spring or weight. Without a trigger mechanism, the system will simply spin uncontrollably, but the trigger mechanism regulates this movement by controlling the periodic oscillations of the pendulum or balance wheel. This allows the gear to rotate evenly with each swing of the pendulum, moving the clock's timing mechanism at a constant speed. The second function of the escapement is to maintain the oscillation of the pendulum or balance wheel by transmitting small shocks to it.

Each swing of the pendulum releases the escapement, moving it from the "locked" state to the "moving" state for a short period that ends as soon as the next gear tooth contacts the locking surface of the escapement. It is this periodic release of energy and rapid stop that makes the clock tick. This sound is made by a gear train when the gear suddenly stops the moment the trigger mechanism is blocked again.

1. History

The importance of the escapement in the history of technology lies in the fact that it is a key invention that made it possible to create all types of mechanical watches. Thanks to this invention in Europe in the 13th century, there was a shift in the development of clock mechanisms from the use of continuous processes (such as the flow of water in a water clock) to periodically repeating processes, such as the oscillation of a pendulum, which could provide greater accuracy.

1.1. Liquid trigger

The first liquid escapements were made in China by the Buddhist monk I Xing, who, together with the statesman Liang Lingzan, used them in 723 (or 725) in armillary spheres and clocks. During the Song era (960-1279), engineers Zhang Xixun (d. late 10th century) and Su Song (1020-1101) improved the escapement mechanisms of their astronomical tower clocks before technology stagnated in China and decline According to Ahmad al Hassan, a mercury escapement in Spain made for King Alfonso X of Castile in 1277 can be attributed to the earliest described in Arabic sources. Knowledge of these mercury triggers may have spread throughout Europe through translations of Arabic and Spanish texts.

However, none of these triggers had sufficient accuracy, since their operation in measuring time depended on the uniform flow of liquid through the hole. For example, in Su Song's watch, water flowed into a container mounted on a pin. The role of the escapement mechanism was to tilt the bowl of the container each time it was filled, the clockwork wheel would rotate at a certain angle, the water would pour out of the bowl, and then the process would repeat again.

1.2. Mechanical trigger

The first mechanical escapements, the pin type, were used for several centuries in bell control devices before they were used in watches. In the 14th century, such mechanisms were installed in the first mechanical clocks in Europe, these were large tower clocks. It is now difficult to establish when they were first used, because it is difficult to distinguish which of the tower clocks of this period were mechanical and which were water. However, circumstantial evidence, such as the dramatic increase in clock construction costs, points to the late 13th century as the most likely date for the introduction of modern escapements. The astronomer Robert Anglicus wrote in 1271 that watchmakers were trying to invent an escapement, but had not yet succeeded. However, most sources agree that mechanical watches with escapements already existed in 1300.

2. Reliability

The reliability of the trigger mechanism depends on the qualifications of the manufacturer and the level of service. Poorly made or poorly maintained devices will have problems. The escapement must accurately translate the oscillations of the pendulum or balance wheel into rotation of the gears of the clock mechanism, and it must transfer enough energy to the pendulum or balance wheel to maintain its oscillations.

In many triggers, the release creates a sliding motion. For example, in the animation shown above, the anchor blades slide along the escape gear tooth as the pendulum oscillates. Blades are often made from very hard materials, such as artificial ruby, but even then they require lubrication. Since lubricating oil dissipates over time due to evaporation, oxidation, etc., relubrication is required periodically. If this is not done, the watch may run unstably or stop altogether, and the escapement parts will be subject to rapid wear. The increased reliability of modern watches is mainly due to more high quality lubricants High-quality watches will be lubricated for five years or more.

Some escapements avoid sliding friction altogether, such as John Harrison's 18th-century grasshopper mechanism or George Daniels' 20th-century coaxial mechanism. There is no need to lubricate the trigger mechanism (but this does not replace the requirement for lubrication of other parts of the transmission mechanism).

3. Accuracy

The accuracy of a mechanical watch depends on the accuracy of the timer device. If it is a pendulum, then the accuracy determines the period of oscillation of the pendulum. If the pendulum rod is made of metal, it will expand when contacted with heat, and the period of oscillation will change. IN expensive watch Special alloys are used to make the pendulum to minimize these deviations. The period of oscillation of a pendulum also varies depending on the amplitude of the oscillations. In high-precision watches, the oscillation arc is kept as small as possible. Pendulum clocks can achieve very high accuracy. Even in the 20th century, pendulum clocks were used in laboratory measurements. The trigger has a big impact on accuracy. The more accurately the pendulum receives an energy impulse, the more accurately the period of its oscillations. Ideally, the impulse should be evenly distributed on both sides of the lowest point of the pendulum's oscillation. This is explained by the fact that pushing the pendulum as it moves towards the lower point of oscillation gives an increase in its energy, and pushing when moving away from this point leads to a loss of energy. If the impulse is uniformly distributed, then it gives energy to the pendulum without affecting the period of its oscillations.

Wristwatches and other small clocks do not use a pendulum as a timer. Instead, they use a balance spring - a thin metal hair connected to a balance wheel. The balance wheel rotates back and forth in good swiss watches- with a frequency of 4 Hz (or 8 ticks per second). Some watches use a higher speed. The length of the hair should not depend on temperature; special complex alloys are used for its manufacture. As with a pendulum, the escapement must give a small push each cycle to keep the balance bar oscillating. The same problem of lubrication is relevant. If the escapement is not lubricated in time, the watch will begin to lose accuracy (as a rule, acceleration occurs).

Pocket watches are the predecessors of modern wristwatch. They were carried in a pocket, so they were usually in a vertical orientation. Gravity causes some loss of accuracy as the mechanism becomes unsymmetrical over time. To minimize this influence, the French watchmaker Breguet invented a special type of escapement in 1795 - the “tourbillon”. In it, the balancer is placed in a special rotating frame (the rotation period is usually one revolution per minute), which allows smoothing out gravitational distortions.

The most accurate mechanical watch was made by the English archaeologist Edward Hall. According to his data, the accuracy of the clock was about 0.02 seconds per 100 days. This clock is electromechanical; it uses a pendulum as a timer, and energy is transferred to it using special relays and electromagnets.

4. Mechanical triggers

Since 1658, when the pendulum and spring balance were introduced, more than 300 types of different mechanical escapements have been developed, but only about 10 of them have achieved widespread use. Almost all of them are described below. In the 20th century, electronic methods of measuring time gradually replaced mechanical watches, so the study of the design of escapement mechanisms became a bit of a curiosity.

4.1. Pin trigger

The pin trigger mechanism shows: (c) - a wheel with a crown, (v) - a pin, (p, q) - blades.

The very first escapement mechanism, which appeared in Europe around 1275, was a pin type, also called a crown pin mechanism. It predates the pendulum and was originally controlled by a foliot, a horizontal bar with a weight at each end. A vertical rod (pin) is attached to the middle part of the folio and has two small plates (blades) sticking out like a flag on a pole. One blade is attached to the top and the other to the bottom of the pin, and they are rotated a little over ninety degrees relative to each other. The escapement gear is made in the form of a crown and rotates about a vertical axis. When the gear begins to rotate, its tooth pushes the upper blade and the foliot begins to move. When the tooth pushes the upper blade, the lower blade rotates and engages. The momentum of the foliot pushes the gear back and eventually the system stops. At this point, the lower blade pushes the foliot and the process repeats. This system does not have its own oscillation frequency, just a certain force pushes the gear all the time and it rotates around its axis by inertia.

At the next stage of development, the same idea was implemented in combination with a pendulum. The axis of the pin became horizontal, half of the foliot disappeared, and the gear wheel rotated around a vertical axis. The same escapement, but much smaller, was used in watches with a balance wheel and a spring instead of a pendulum. John Harrison's first marine chronometer used a highly modified pin mechanism, which turned out to make a good timer.

4.2. Anchor release mechanism

Anchor trigger mechanism.

Invented around 1660 by Robert Hooke, the anchor quickly replaced the pin and became the standard for use in pendulum clocks until the end of the 19th century. Its advantage is that it reduced the amplitude of the pendulum's oscillations to 3° - 6°, as a result of which the pendulum became isochronous. It allowed the use of longer, slower-moving pendulums that required less energy. Thanks to him, long narrow floor and wall pendulum clocks appeared (in some countries they are called “grandfather clocks”), which can still be found in our time.

The anchor mechanism consists of an escapement gear with reversely inclined teeth and an anchor-shaped “anchor” that rotates above it from side to side and is connected to the pendulum. The anchor has curved blades at the ends, which alternately enter the gear teeth, receiving impulses. Mechanically, its operation is similar to the pin mechanism, and it has adopted two disadvantages from the pin mechanism: (1) the pendulum is constantly pushed by the gear teeth in each cycle, it cannot oscillate freely, thereby disrupting its isochronism; (2) this trigger mechanism has recoil, the anchor in its cycle pushes the gear in the opposite direction. This causes backlash, which increases wear on the watch mechanism and reduces accuracy. These shortcomings were eliminated in the bestik escapement, which gradually replaced the anchor escapement in precision watches.

4.3. Bestial trigger mechanism

Bestial trigger mechanism. Shown: (a) - escapement gear (b) - blades, concentric locking surfaces shown (c) - pendulum strut.

The bestless trigger mechanism is an improvement on the escapement mechanism. It was first made by Thomas Tompion from a design by Richard Townley in 1675, although Tompion's successor, George Graham, is often cited as having popularized it in 1715. In an anchor escapement, the oscillations of the pendulum for part of its cycle push the escapement gear in the opposite direction. This “kickback” interferes with the movement of the pendulum, resulting in reduced accuracy, and reverse gear movement causes a “backlash” effect and creates high loads on the system, which leads to increased friction and wear. The main advantage of a stickless mechanism is that it eliminates these recoils.

In a stickless mechanism, the vanes have a second curved “locking” surface concentric with the anchor's axis of rotation. At extremes of the pendulum's oscillations, the tooth of the escape wheel becomes stationary on this surface, without transmitting the impulse to the pendulum, which causes a rollback. Near the bottom position of the pendulum, the tooth disengages from the locking surface and engages the sharp-angled "impulse" surface, giving a push to the pendulum before the blade releases the tooth. This was the first mechanism with separate blocking and impulse surfaces. The bestik mechanism was used for the first time in a watch with precise movement adjustment. Due to its higher accuracy, it replaced the anchor mechanism. The bestik mechanism is used in almost all modern pendulum clocks.

4.4. Lever trigger

The lever escapement was used in the vast majority of watches after 1800. It is accurate and fairly easy to manufacture. It is also self-starting, so if the watch is shaken so that the balancer stops, it will automatically start working again. There are several types of lever triggers. The original type was a tripod type, in which the lever and balance wheel were always connected by a gear. Later it became clear that all the teeth from the gear could be removed, with the exception of one. This is how the disconnected lever trigger mechanism appeared. Not only is it lighter and easier to make, but it is also significantly more accurate. The lever can be positioned so that it is at right angles to the escapement gear, an option favored by British watchmakers. Or, the lever can be placed inside the balancer and inside the escapement gear; this option is preferred by Swiss and American watchmakers. Finally, $1 watches use a very primitive type of lever escapement called a paddle escapement.

Internal or Swiss lever trigger.

4.5. Duplex (two-way) trigger mechanism

The duplex escapement was invented by Robert Hooke around 1700, improved by Jean Baptiste Dutertre and Pierre Le Roy, and finally perfected by Thomas Trayer, who patented it in 1782. It was used in quality English pocket watches from 1790 to 1860, and in Waterbury, in cheap American consumer watches, during 1880-1898. In a duplex mechanism, as in the chronometer with which it bears similarities, the balance wheel receives an impulse only in one of the two oscillations of the cycle. The escapement gear has two sets of teeth (hence the name "duplex"). The long stop tooth is made on the balancer side, and the short impulse (pushing) tooth protrudes axially from above. The cycle begins when the retaining tooth is against the ruby disc. The balancer begins to move counterclockwise through the center position, the groove of the ruby disc frees the tooth. When the balancer begins to move back, the blade in the extreme right position receives a push from the impulse tooth. At this time, the locking tooth hits the roller of the ruby disc and remains there until the balancer completes the clockwise oscillation cycle, then the process is repeated. During clockwise movement, the impulse tooth quickly drops into the groove of the ruby disk and remains there.

The duplex mechanism refers to mechanisms with static friction; the balancer is never completely free from the trigger mechanism. As with a chronometer, there is little sliding friction during an impulse because the impulse tooth and blade move almost parallel, so little lubrication is necessary. The duplex mechanism is at least as accurate as a lever mechanism, and perhaps approaches chronometer-like. However, the sensitivity of the duplex mechanism to shaking made it unsuitable for active people. Like the chronometer, it is not self-starting; if it suddenly stops while the balance wheel is moving clockwise, it cannot start again.

Duplex trigger mechanism, shown: (A) - escapement gear, (B) - locking tooth, (C) - impulse tooth, (D) - vane, (E) - ruby disk. The blade and disk are attached to the axis of the balancer, which is not shown in the figure.

4.6. Grasshopper trigger

A rare but interesting escapement is the John Harrison grasshopper escapement. In it, the pendulum is driven by two articulated arms (blades). When the pendulum oscillates, one lever engages the gear and moves it slightly back. This releases another lever, which moves back, freeing the gear. When the pendulum moves in the opposite direction, the second lever engages the gear, pushes it and releases the first lever, and so on. The grasshopper mechanism is much more difficult to manufacture than other escapements, so it is very rare. The grasshopper mechanism made by Harrison in the 18th century still works. Most mechanisms wear out much faster and consume much more energy.

4.7. Gravity trigger

A gravity escapement uses a small weight or small spring to transfer momentum directly to the pendulum. The first design consisted of two arms of a lever, which rotated very close to the pendulum's suspension point, the arms were located on different sides of the pendulum. An inclined shoulder blade is attached to each shoulder. When the pendulum lifts one arm high enough, its blade releases the escapement gear. Almost immediately, another tooth on the escape gear begins to slide up the surface of the other arm, thereby lifting it. He raises the spatula and stops. Meanwhile, the first tooth is still in contact with the pendulum and drops below the point where contact began. This decline gives impetus to the pendulum. The design was developed gradually from the mid-18th to the mid-19th centuries. Ultimately, this mechanism was chosen for the tower clock. Recently, it has been improved and turned into a special inertial-gravity trigger mechanism, invented by James Arnfeld.

5. Electromechanical triggers

At the end of the 19th century, electromechanical escapements for pendulum clocks were developed. In them, a relay or photo relay switches an electromagnet in time with the oscillations of the pendulum. Electromechanical escapements are among the best. In some watches, the electrical impulses that move the pendulum also control the movement of a plunger that turns a gear.

5.1. Hipp's watch

In the mid-19th century, Matthias Hipp invented an electromagnetic pulse switch for watches. The pendulum moves a gear with a ratchet through a pawl, and this gear moves the rest of the clock mechanism. The pendulum does not receive an impulse on every swing, or even on every second swing. It receives an impulse only when the amplitude of the oscillations falls below a certain level. Like the pawl of the indicator mechanism, the pendulum is also equipped with a small weather vane; when it turns upward, the pendulum swings completely freely. When the amplitude of the pendulum's oscillations is large enough, the weather vane falls into the groove and the pendulum does not touch it. If the amplitude of oscillation decreases, the weather vane leaves the groove, the pendulum engages it and pushes it down. The electromagnet circuit is closed, which sends an impulse to the pendulum. The amplitude of the pendulum's oscillations increases and the process repeats.

5.2. Free pendulum clock

In the 20th century, William Hamilton Short invented the free pendulum clock, patenting it in September 1921. They are manufactured by Synchronome and are accurate to a hundredth of a second per day. In this system, the “main” pendulum, the rod of which is made of a special steel alloy with 36% nickel (Invar) and the length of which is almost independent of temperature, oscillates free from external influence, if possible in a closed vacuum chamber, and does not do any work . It has mechanical contact with the trigger every 30 seconds and only for a fraction of a second. The secondary "slave" pendulum rotates a ratchet, which switches an electromagnet every thirty seconds. This electromagnet releases the gravitational escapement of the main pendulum. A fraction of a second later, the movement of the main pendulum disables the trigger mechanism. The gravity escapement gives a tiny impulse to the main pendulum, which keeps the pendulum swinging.

Notes

Cipolla Carlo M. Clocks and Culture, 1300 to 1700 - books.google.com/books?id=YSf9MVxa2JEC&pg=PA31&dq=verge escapement technology&sig=6ZbQh-an59yCcesR1mjn1p8w-H4. -W.W. Norton & Co.. - P. 31. - ISBN 0393324435
Needham, Joseph (1986). Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 2, Mechanical Engineering. Taipei: Caves Books Ltd. Page 165.
Ahmad Y Hassan, Transfer Of Islamic Technology To The West, Part II: Transmission Of Islamic Engineering - www.history-science-technology.com/Articles/articles 71.htm, History of Science and Technology in Islam.
Headrick, Michael (2002). "Origin and Evolution of the Anchor Clock Escapement - www.geocities.com/mvhw/anchor.html." Control Systems magazine, 22 (2).
Hall, E.T. The Littlemore Clock - www.iinet.com/~holmstro/hsn_article.php. NAWCC Chapter 161 - Horological Science - www.iinet.com/~holmstro/hsn_entry.html. National Association of Watch and Clock Collectors (1996).
Britten Frederick J. Watch and Clockmaker's Handbook, 9th Edition - books.google.com/books?id=5SYJAAAAIAAJ&pg=PA108. - E.F.& N. Spon. - P. 108.
Smith, Alan (2000) The Towneley Clocks at Greenwich Observatory - www.mikeoates.org/mas/history/lectures/20001116.htm Retrieved 2009-03-27

The first mechanical watch with an anchor mechanism was made in Tang China in 725 AD by masters Yi Xing and Liang Lingzan. From China, the secret of the device apparently came to the Arabs.

On this moment Europe's oldest tower clock is in Grodno, Belarus. They have been in working order for over 500 years. .

Later, pocket watches appeared, patented in 1675 by H. Huygens, and then - much later - wristwatches. At first, wristwatches were only for women, jewelry richly decorated with precious stones, and characterized by low accuracy. No self-respecting man of that time would have put a watch on his hand. But the wars changed the order of things and in 1880 the Girard-Perregaux company began mass production of wristwatches for the army.

Mechanical watch design

A mechanical watch consists of several main parts:

The source of energy is a wound spring or a raised weight.
An escapement mechanism is a device that converts continuous rotational motion into oscillatory or reciprocating motion. The escapement determines the accuracy of the watch.
The oscillatory system is a pendulum or balance beam (balance).
The mechanism for winding and moving the hands is a remontoire.
The gear system connecting the spring and the trigger mechanism is an angrenage.
Dial with arrows.

Pendulum

Historically, the first oscillatory system was the pendulum. As is known, with the same amplitude and constant acceleration of free fall, the frequency of oscillation of a pendulum is constant.

The pendulum mechanism includes:

Pendulum;
An anchor connected to a pendulum;
Ratchet wheel (ratchet).

The accuracy of the stroke is adjusted by changing the length of the pendulum.

The classic pendulum mechanism has three disadvantages. Firstly, the frequency of oscillation of a pendulum depends on the amplitude of the oscillations (Huygens overcame this drawback by making the pendulum oscillate along a cycloid, rather than along an arc of a circle). [Galileo published a study of pendulum oscillations and stated that the period of oscillation was independent of its amplitude (this is approximately true for small amplitudes).] Secondly, pendulum clocks must be mounted motionless; They cannot be used on moving vehicles. Thirdly, the frequency depends on the acceleration of gravity, so a clock calibrated at one latitude will lag behind at lower latitudes and advance at higher latitudes.

Balance

Moon phases

Self-winding has a positive effect on accuracy (the spring is constantly in an almost wound state). In waterproof watches, the threads that tighten the crown wear out more slowly.

Automatic watches are thicker and heavier than manually wound watches. Women's self-winding calibers are quite capricious due to the miniature nature of their parts. Automatic winding is useless for people who are sedentary (for example, those who are elderly or in a sick condition), as well as for people who wear their watches only occasionally. However, if there is a special device for automatic winding of watches called a “winder”, the watch can be constantly wound. Winders operate from household electricity (220v or 110v) or from rechargeable batteries.

Tourbillon

In the first mechanical watches, the accuracy of time could depend on the position of the watch in space and the ambient temperature. To reduce the dependence on temperature, special alloys with low temperature coefficients began to be used.

Power reserve indicator

Shows how many more hours or days the spring will last.

Special types of watches

Alarm

At the moment specified by the user gives sound signal. The signal time is set using an additional arrow. The alarm clock usually rings 2 times a day with a traditional 12-hour clock face and 1 time with a 24-hour clock face

Time control in chess. Just like stopwatches, they are designed to measure relative time.