Clock

from Wikipedia, the free encyclopedia

The clock is a measuring device that can display the current time or measure a period of time . In its development history spanning several millennia, from the simple elementary clock to the high-precision atomic clock , it has been and is in complex interaction with the cultural , technical and social development of mankind.

The clock represents a fundamental parameter of human coexistence - time. In symbolism and art it stands for the perpetual flow of time; as a vanitas motif for transience and one's own mortality. It also appears in depictions as an indication of wealth or as an attribute of moderation .

Today the watch has become an indispensable companion in the most diverse areas of everyday life. The wristwatch accompanies its wearer as a constantly available time display. The electronic clock can be found in many everyday objects, from household appliances to televisions and radio alarm clocks to computers and cell phones .

High-precision time systems (world time, atomic time) have been established for science and space travel , which are available everywhere through time signal transmitters and satellite radio. In astronomy, times are measured down to the millionth of a second, while the atomic clocks of GPS satellites now work better than nanoseconds and the time of flight measurement of electromagnetic waves even reaches accuracies of 10 −14 .

Although elementary and wheel clocks have lost their central role in measuring time, they are still very popular with enthusiasts and collectors of antique pieces.

Early iron clock

etymology

The word “clock” comes from Middle High German ūr (e) / or ( bell ) (“hour”, “clock”), this from Middle Low German ūr (e) , which, like English hour , is borrowed from old French (h) ore . It is based on late Latin / Italian ora , from Latin hōra , from ancient Greek ὥρα / hóra (" time ", " hour " from Urindo-European * yōr-ā (related to year ).

In English, a distinction is made between watch (especially wristwatch and pocket watch) and the larger clock (for example as a table clock, wall clock or grandfather clock as well as large clocks on towers or houses).

History and Development

Antique sundial (Skáphe)
Water clock with float, counterweight and dial to display the time

antiquity

Even in ancient times, humans divided their daily routine by observing the celestial stars, the sun and the moon . Rising and setting of the sun as well as its highest point at noon were striking times for the people; the time could be divided by simple markings on the wandering shadow. The shadow clock was developed from this in ancient Egypt . The days were divided into a certain number of seasonal hours , the length of which, however, changed steadily with the seasons. Since the Middle Kingdom at the latest , diagonal star clocks were in use whose hour division was based on the movements of constellations and based on the equal hour principle. Coffin texts of the respective epoch indicate that, according to Egyptian mythology , the diagonal star clocks were intended to help the deceased ascend into the sky.

Since the 16th century BC The use of the water clock is known in ancient Egypt. The official Amenemhet invented a water clock with an improved time measurement during the reign of Amenhotep I. Water clocks consisted of a vessel into which water either ran in or out. The time could be read from the water level independently of the daylight and in regular time units. Water clocks thus allowed the use of the even, equal hours, which were used in a modified form in Babylonia, for example as Danna . Later, the water clocks were also equipped with floats connected to gear trains, which made it possible to display the time on dials. In Greece, these clocks were used to limit speaking time in court. The phrase "time is up" can be traced back to this.

The technique of sundials and water clocks was adopted by the Romans and spread throughout the Roman Empire . In Trier , the Roman Augusta Treverorum , the foundation walls of a tower were discovered in 1913, which is likely to have been almost identical to the Tower of the Winds , a combined sundial and water clock in Athens . It can be assumed that these techniques were known in Central Europe by the time of the Germanic provinces of Rome at the latest, even if the knowledge was lost for centuries with the decline of the Roman Empire.

There followed a heyday of science in Islamic countries. Arabs and Moors did research in various fields and made great achievements in mathematics, timekeeping, and astronomy. Magnificent water clocks, which were equipped with complicated figure automatons, are known from the Arab world. An impressive example is the elephant clock of al-Jazarī , another is the water clock with automatons, which Charlemagne received from the caliph Hārūn ar-Raschīd in 807 . In addition to the water clocks, the astrolabe , an originally Greek measuring instrument for determining the position of the stars and the time, was further developed. The astrolabes found their way back to Europe and slowly, especially in monasteries, the scientific basis for independent production emerged. Such astrolabes can be found on many medieval monumental clocks.

Replica of a tower clock
Astronomical clock at Heilbronn town hall
Pendant watch, signed by Charles Bobinet, Paris around 1650

middle Ages

In addition to the sundials and water clocks, the candle clock also established itself in Europe from 900 AD . Candles with defined shapes and sizes burned down within a certain period of time, and markings indicated the elapsed time. These clocks could not only be used independently of daylight, but were also easy to use and readily available. In addition to candles, oil lamps , slow-burning fuses and, in China, fire watches , some with changing fragrances over time, were also used.

Medieval life was regulated by a multitude of bells from the church and city towers. Not only the prayer times of the monasteries, but z. B. opening times of city gates, court and market times and other important times of the day and night were rung in by the towers . This required a reliable display of the time; a necessity that the sundials and water clocks did not meet.

The escapement must be regarded as an epoch-making invention , which first made the development of the wheel clock possible. Gears have been used since pre-Christian times and complicated automatons were known from the Arabic water clocks, but it was the escapement that turned the freely running gear into a clock. It is not known when the mechanical watch was used.

The wheel clock was quickly used by tower keepers to indicate the right time for the bells to strike. Initially, the tower clock hung in the tower's room with an alarm clock and an hour strike, later it was used as a large, wrought-iron tower clock in town halls, church and clock towers to display the time to the general public. The governor of early wheel clocks was the Foliot , a simple but robust device that allowed rates of accuracy of around 10 minutes per day. These clocks were set to the respective local time with the help of sundials or noon clocks .

The first written mention of a wheel clock dates back to 1335 and refers to a device in the chapel of the Visconti palace in Milan. With the invention of the strike clock , it was possible for the first time to read equinox hours mechanically in 1344 . In 1370 was in Paris a first publicly visible striking clock in the Tour de l'Horloge corner tower of that Palais de la Cité attached. In the 14th century many public wheel clocks were created in rapid succession in Europe, of which around 500 are still documented today. In addition, a large number of clocks can be assumed that were not mentioned in a document.

In particular, the findings from astronomy and mathematics had a major influence on the development of the wheel clock at this time. Several monumental astronomical clocks with a variety of intricate displays were made during this period. For European monarchs and wealthy citizens, smaller iron clocks were made according to the same principle. Although they also had astronomical displays, they were mostly used for representative purposes. At the same time, the change from the public to the domestic clock took place.

Hourglasses spread in Central Europe at the same time as the wheel clocks in the 14th century. The centers for their production were Nuremberg and Venice , which had suitable sand deposits. Hourglasses are only suitable for measuring comparatively short time intervals and were e.g. B. in shipping to determine the cruising speed and as a bell clock in use until the 19th century.

Initially, apart from a few individual artists, wheel clocks were mainly made and repaired by locksmiths or gunsmiths who were already organized in guilds in the High Middle Ages. From their ranks, masters specialized in the craft of watchmaking . Independent watchmaker guilds existed as early as 1450, e.g. B. in Vienna , demonstrable. Very early after the invention of the iron wheel clock, there were also attempts to build such clocks out of wood. Tower clocks, some of which were made of wood, are also known. Contrary to the usual opinion, the first wooden wheel clocks were by no means simple objects of daily use, but were often artfully made and intended for princes or high clergy. It was not until the early 17th century that simple wooden wheel clocks began to spread rapidly and widely in Central Europe, especially in Switzerland, France and southern Germany.

Modern times

Table clock after Peter Henlein (replica)

The era of the Renaissance saw two significant developments that had a decisive influence on the way the clock continued.

On the one hand, domestic clocks were given a case to protect them from dust and thus from wear and tear. From then on, the shape of the clocks was subject to the respective tastes and fashions of their time, and it was not uncommon for the function of time measurement to take a back seat to the decoration of the external shape.

On the other hand, it became possible to keep making watches smaller and smaller thanks to new inventions, different materials and better tools. By using brass for the gears, they could be made much smaller. The spring , which is already known from door locks , was adopted as an energy store for the clockwork , making it independent of the location. The oldest preserved wheel clock with spring drive and spring winding dates from around 1430 ('The clock of Philip the Good of Burgundy ' in the Germanic National Museum ). Around 1504, Peter Henlein from Nuremberg was one of the first to install a spring drive in connection with a Unrast in a watch and was able to reduce it to pocket size. The watch was not only independent of where it was set up, it could also be worn and continuously display the time. Examples for the miniaturization of the clock are a clock made in 1620 with a diameter of 5.75 lines by Martin Hylius from Dresden and one from 1648 by Johann Ulrich Schmidt from Augsburg with a diameter of only 4 lines. The first pocket watches with a spindle escapement were made from the middle of the 17th century. Many important watchmakers in England, France and Germany produced pieces of the highest quality and competed in their continuous improvement. In America they followed a different path, from the early 19th century onwards they focused on the manufacture of particularly inexpensive pocket watches with industrial mass production.

The development of the clock was divided into two main types of clock , the fixed large clock and the portable small clock , to which fundamentally different requirements were later made.

Jost Bürgi: Mechanical celestial globe, manufactured in Kassel in 1594, now in the Swiss National Museum in Zurich
John Harrison's Chronometer H5

Many table clocks have survived as typical examples of Renaissance clocks. They are characterized by movements with a spindle escapement and wheel balance, barrel with power transmission via gut strings and worms, wheels made of fire-gilded brass or copper, work plates made of brass and profiled pillars. Some of them have an hour or quarter hour strike on the bell and alarm clock . The housings have a basic geometric shape, are made of gold-plated brass or bronze and openwork in filigree work. Rare examples have astronomical displays or imaginative, figurative automatons.

Even before the pendulum was introduced, clocks with minute hands were being built in a few cases. Pieces by Jost Bürgi are known from the 16th century that even had sub-dials for second hands, even if the accuracy of the clocks only allowed such precise time measurement from around 1700 onwards.

On the threshold of the Baroque era , the representation of figures and the design variety of watch cases became more and more important (example: Cartel clock ). From 1600 at the latest, many splendid designs with cases in animal shapes and made of precious metals such as silver and gold came from the German centers of Augsburg and Nuremberg. The importance of the mechanical precision of timekeeping took a back seat to the fascination for the machine with its wonderful functions.

With the introduction of the pendulum as a rate regulator, a revolutionary discovery took place that laid the foundation for scientific chronometry and the construction of precision clocks. Galileo Galilei , a brilliant scientist and pioneer of the Copernican worldview , described the pendulum laws in 1583 and discovered isochronism . He devised a mechanism with a free escapement and pendulum, which he could no longer complete during his lifetime. In 1656, the Dutch astronomer, mathematician and physicist Christiaan Huygens developed the same idea independently of Galilei and had the first pendulum clock made by Salomon Coster . A short time later, around 1680, William Clement developed the lever escapement for large clocks. The wheel clock achieved an unprecedented precision of an average of a few seconds rate deviation per day. As a result, the regulators of many old clocks were replaced by pendulums and the minute hand was generally introduced.

Watchmaking focal points in the following period were the Netherlands and England, especially London. The main features of the essential Dutch clock types, Haagse Klok , Stoelklok and the Frisian clocks can be traced back directly to the clocks built by Salomon Coster. In England, with the introduction of the lever escapement, the first floor clocks , the so-called grandfather clocks , emerged, which together with the bracket clocks became synonymous with English clocks. The pendulum clock as a medium-sized pendulum clock that can be placed on a table or a wall console developed in France (Blois and Paris) with different case styles and regional shapes, and later also in Switzerland (Neuchâtel and Geneva). In Germany the importance of the pendulum was long misunderstood and so the German centers Augsburg and Nuremberg lost their leading role and fell behind.

Between 1720 and 1780, so-called carriage clocks, especially large pocket watches with striking and occasional musical mechanisms, were very popular as travel clocks in England . They were later replaced by the Carriage Clock and the French Pendule d'Officier .

The flourishing, but also competing, trade between European powers and the colonies overseas made the highest demands on shipping . Precise timing was essential for safe navigation . The search for a solution to the longitude problem , i.e. the determination of the geographical longitude on the open sea, lasted over 150 years despite the enormous prize money being awarded. The problem was finally solved in 1759 by John Harrison with the construction of his marine chronometers .

Modern

As a result of industrialization , mass production of clocks developed in various centers from the middle of the 19th century. In Germany, watch production in the Black Forest was particularly important, in France the development of the Comtoise watch may serve as an example. In the United States , the industrial-made pocket watch became particularly popular. After initially very high-quality production, the pocket watch quickly turned into a successful mass-produced item. The so-called dollar watch , a simple type of watch for everyone, was sold many millions of times by various manufacturers up until the 20th century.

Precision pendulum clocks from Sigmund Riefler

At the end of the 19th century, Strasser & Rhode and Sigmund Riefler developed precision pendulum clocks in Germany , which were the most accurate clocks for many years and were mainly used for time service purposes and astronomical observations .

Advances in precision mechanics and later in electronics also made it possible to manufacture very sophisticated pocket watches with a grand complication .

With the advent of nationwide power supply, the desire to use electricity for clocks quickly arose. A first step in this direction was the winding of clockworks using a mains-fed electric motor . Tower clocks with heavy weights and precision clocks, which should run as undisturbed as possible, were equipped with it. Electrically wound balance watches were z. B. used in time switches .

The speed regulator (pendulum or balance) of mechanical clocks can also be driven electromagnetically and turn the gear train via a pawl. Such clocks were available, for example, as wall clocks with a "balance wheel" that carried permanent magnets and was driven by fixed coils. However, many of the electric pendulum clocks sold today only have a pendulum pendulum, the clock itself is driven by a quartz movement.

For the rapid expansion of supraregional rail traffic , it was necessary to transmit time signals over long distances. Master clocks in public clock systems sent electrical impulses to remote slave clocks , which were driven by a simple stepping mechanism, to synchronize the time. This also heralded the end of the regional local times and led to a social change.

Synchronous clocks use the network frequency of the alternating current network as the time standard. They are inexpensive to manufacture and were widely used as large clocks in industry and public institutions.

As early as the beginning of the 19th century, miniature watches were occasionally built into decorative straps and worn on the arm. They can be seen as the forerunners of modern wristwatches, which were first mass-produced for the German Navy around 1880. After the turn of the century, the wristwatches initially prevailed as neat ladies' watches over the much larger pocket watches. Especially in the trench warfare of the First World War , the wristwatch proved its practical advantages over the pocket watch and experienced the first significant improvements, such as: B. Luminous hands and screwed housing against moisture. But athletes and pilots also relied on the advantages of the wristwatch early on.

The invention of the automatic watch by John Harwood (1923) and the introduction of the waterproof watch by Hans Wilsdorf ( Rolex Oyster , 1926) helped the wristwatch to achieve its final breakthrough . The development of shock protection was a further step towards everyday suitability. By 1930 the wristwatch had already reached the sales figures for pocket watches, and by 1934 it dominated two thirds of the market.

Digital radio clock
One of the cesium atomic clocks at PTB in Braunschweig

The first quartz watch was developed by HM Dadourian in 1921 , based on ultrasonic experiments with quartz crystals carried out by Paul Langevin shortly after the First World War . The clock generator of a quartz watch is not a mechanical pendulum or a balance wheel, but an electronic quartz oscillator, the frequency of which is adhered to with the help of a quartz oscillator.

Initially, such watches were not available as a consumer good, but at the beginning of the 1970s they established themselves on the market due to their high accuracy at a moderate price and very little maintenance and led the traditional watch industry into the quartz crisis . The classic wheel clock has been completely replaced by the quartz clock in almost all areas of life. For several years now, it has been experiencing a remarkable revival as a wristwatch.

Kitchen clock with short-term alarm clock (1956)
Pocket watch as a shop sign

A final step towards the currently highest accuracy of time measurement was the development of the atomic clock , which was used for the first time in 1949. Atomic clocks use the radiation transitions of free atoms or ions as timers and are used in science, for navigation in space travel and as a time standard.

Clocks whose time display is controlled by a radio signal are called radio clocks . Since the 1960s , all accessible radio clocks in Central Europe can be synchronized by time services . They have been compared with atomic clocks of the Federal Office of Metrology since 1966 by the first European time signal transmitter HBG and since 1967 by the time signal transmitter DCF77 with an atomic clock of the Physikalisch-Technische Bundesanstalt . The Bureau International des Poids et Mesures in Paris uses the readings from over 260 atomic clocks at over 60 institutes around the world to set the International Atomic Time (TAI) as the reference time. In recent years, a whole host of additional electronic distribution mechanisms has been established for time signals via the RDS service of the FM car radios, the teletext and Electronic Program Guide (EPG) and TV via the NTP protocol of the Internet are accessible .

Many people use the time display on their cell phones and smartphones . These are mostly synchronized via your network provider or via the general Internet .

Milestones and important discoveries

Assemblies of a wheel clock

The following section describes the assemblies of a classic gear clock . Elementary clocks and electronic clocks work on fundamentally different principles.

A gear clock consists of the four assemblies energy storage, gear train, speed regulator and display. The drive energy supplied by the energy store and transmitted by the gear train is transferred to the gear regulator by the escapement and maintains its oscillation. The gear regulator in turn controls the escapement, which divides the movement of the movement into an even cycle. The display is switched by the gear train in this cycle, on it you can read the time.

Energy storage

The simplest and oldest method of driving a wheel clock is to use a slowly falling weight. The weight can be attached to the drive wheel of the clockwork with a rope , a gut string or a chain . The heavier the weight and the larger the drive wheel, the higher the torque to drive the movement .

A weight drive is easy to construct and provides constant driving force. The running time of a weight watch is limited by the height of the weight (actually the mass). If the weight can "no longer fall", the watch is opened with a key over the winding square or, e.g. B. with cuckoo clocks and house clocks , pulled directly over the chain hoist. Tower clocks with heavy weights often have an electric drive that takes on this task.

Another way of storing mechanical energy is to use a clock spring. It is mostly a long coiled spiral spring . In very simple movements the spring is exposed, in more technically sophisticated watches it is protected in a barrel . The advantage of the spring drive lies in the possible downsizing of the movement and the fact that the drive is independent of the position, which made it a prerequisite for the development of portable watches.

The drive torque delivered by a coil spring is not constant. The further the clock runs down, the more the torque decreases. Further constructive techniques are required for consistently good performance of the watch. Because of the limited spring length, only a small amount of drive energy can be stored.

Electric clocks are supplied with energy directly from the power grid , from a battery (e.g. a button cell ) or from a photovoltaic cell .

Gear train (translation)

The totality of all gears and drives of a clockwork is the gear train . In the past, wood, iron, steel or brass were used as materials. In modern clocks, plastics or z. B. Ceramic application.

The movement transfers the drive force made available by the energy storage device to the gear regulator with the help of the escapement . By combining different pairs of gearwheels, a gradation of the individual cycle times is achieved so that the energy store only runs very slowly, while the escape wheel rotates relatively quickly.

Many mechanical watches have a striking mechanism that is triggered by the movement at certain times and emits an acoustic signal. Movement and striking mechanism are usually separate in the watch, either next to or behind one another. The striking mechanism has no escapement, but is often equipped with a simple aerodynamic brake - the vestibule - so that it does not run too quickly. It carries out the blows and moves a mechanism to control them (number and sequence of blows). After it has been triggered by the walking mechanism, a striking mechanism runs once. It turns itself off and remains in peace until it is triggered again. Bells or gong sticks are usually used as sound bodies.

In addition, there are call and repetition striking mechanisms which, on request, strike the time exactly to the minute or repeat the last strike, or repeat the strike automatically after a few minutes.

In the case of complicated clocks, additional works are added, e.g. B. a calendar movement or a chronograph movement . Further additional equipment (complications), such as a complicated wristwatch, can be a moon phase display, an alarm clock or a repeater.

Regulator

The regulator of a mechanical watch generates regular, recurring time cycles. It receives its drive energy from the energy store as an impulse via the escapement of the clock. In the opposite direction, the escapement receives the timing from the regulator and interrupts the movement of the movement.

The first regulator was the Foliot , a horizontally arranged bar whose moment of inertia could be changed by small weights at the ends of the bar. The Unrest was a further development of the Foliot in the form of a circular ring. The early regulators were still imperfect because they were firmly connected to the escapement and their inertia merely stabilized the rotation of the escapement.

In 1656 the Dutch astronomer Christiaan Huygens invented the clock pendulum in its current form, with which the accuracy of the wheel clocks improved by leaps and bounds. The Huygens pendulum is decoupled from the escapement and can develop its own oscillation. In 1674 Huygens also developed the balance , which is still the definitive regulator for small watches to this day. The energy change takes place between the movement of the balance mass and the elastic deformation of the associated spiral spring .

In the same way as the escapements, the regulators were always the focus of horological pursuit of perfection. In particular, the attempt to compensate for external influences such as air pressure and temperature changes led to the development of numerous special designs.

However, there were also other solutions with clock generators, e.g. B. 1595 the ball barrel clocks of the chamber watchmaker Christoph Margraf . The continuous speed control with a centrifugal governor used in mechanical engineering was also tried, but turned out to be too imprecise for clocks ( rotary pendulum ).

Time display

Dial of a wrist watch
24 hour display in Curitiba , Brazil
Diverse display of the tower clock (around 1920) in Lier (Belgium)
A "liquid chronometer" in Ilmenau . It shows the time through columns of liquid

The classic form of the time display (also: indication ) is analogue with clock hands on a dial . Early wheel clocks only had an hour hand; the minute and second hands were not generally introduced until around 1700. The first second hand with its own scale became in use from 1780.

The dial is usually a circular or square disk made of metal, wood or glass. The number ring is painted, printed or engraved on it and usually divided into 12 hours. On many wristwatches, the minute and hour indices are placed on the dial. The clock hands are usually arranged centrally, but there may also be sub-dials or cutouts for additional displays. The astronomical clocks in particular inspire with a wealth of different displays.

As the face of the watch, the dial was and is particularly subject to the intended use and the fashionable taste. Particularly distinctive and often stylistically reduced dials are used for example. B. in clocks with technical areas of application that require good readability. Examples are the pilot's watch and the diving watch or the precision pendulum watch . In the case of modern wristwatches in particular, manufacturers take advantage of the opportunity to differentiate themselves from other manufacturers by means of a special dial design and additional displays. In general, the direction of rotation of the hands is clockwise, which imitates the apparent course of the sun in the sky of the northern hemisphere and thus the course of the shadow of a gnomon (staff) on a sundial . The term "clockwise" is derived from this. In 2007 it was decided in Bolivia to turn the clock on the congress building to the left to demonstrate independence from the states of the northern hemisphere.

In the 19th century, there were the first designs for wheel clocks to display the time numerically with a leaf display. However, this form of display only became more widespread with the spread of the digital clock (from English: digit , number; numerical display as the opposite of the dial display ). Only four digits appear in the field of vision as the current time. Other digital displays are clocks that show the time in words - conventional clockworks or computer clocks can set the pace as the inner workings. Or the time is given acoustically (e.g. as a clock for the visually impaired as with the telephone time announcement ) or via a text field.

For the blind and visually impaired, there are wristwatches with an analog display with 2 hands, which can be scanned with the fingertips thanks to knobs - on the pointer ends and as scale lines - after opening the transparent watch glass.

The light signal clock is a special form. Here the time is indicated by countable, discrete individual elements that have to be interpreted digitally. The first of its kind is the linear clock in Kassel, a large variant with the same function is located on the Rheinturm in Düsseldorf .

Wristwatches are typically designed to be worn on the left wrist (slightly above) and are therefore designed for right-handers. If the forearm is bent and held in front of the body at sternum level, the hand is turned inward and the position is held steady for about 1 second - the clock reading gesture - the 12 (to 1) o'clock mark points forward away from the body. The crown for winding and setting the watch by hand is usually mounted on the right at 3 o'clock and is therefore easily accessible with the right hand. Other operating elements, such as the button for lighting / activating the digital display (especially when the LED display used a relatively high amount of power, the operating buttons of a stopwatch are installed in the half-past two to half-past five o'clock). These elements are typically with the index or middle finger When the watch is held upright at 12 o'clock on the right wrist, the thumb of the left hand presses the buttons, which in this case come into conflict with the shirt cuff and can slip over shirt cuffs sometimes have two buttons along a circumference so that they can be set further for wearing a watch .

Central, coaxial pointers are usually mounted so that the axis of the faster moving pointer rotates within the hollow axis of the slower moving pointer. If only one pointer that has become loose falls off, it is the fastest one. October 2016, the minute hand fell from the clock tower of St. Catherine's Church in Hamburg .

Automat, musical mechanism and glockenspiel

Many clocks have other mechanisms driven by gear trains. These include machines, musical mechanisms and glockenspiels.

An automaton is a mechanically moving, figurative representation, usually in human or animal form, which is triggered and driven by the clockwork. A simple example is the cuckoo in cuckoo clocks , moving to strike the clock. However, machines were not always used to display the time, they were often a decorative accessory to the clock for the amusement and fascination of the beholder. The marriage of clocks and automatons was in the Renaissance.

In close relationship to the music boxes standing musical mechanism . In early designs, ringing steel lamellas were struck by a pin roller or hammered hammers were moved that struck bells ( carillon ). The musical mechanisms of flute and organ clocks also work according to this principle. Around 1800 Philippe Samuel Meylan introduced a pin washer to replace the pin roll, which reduced the size.

Glockenspiels , which produce entire melodies by striking church bells , are mainly found in connection with public tower clocks. B. built into pocket watches. It is essentially an extended striking mechanism.

The hourly chimes, which are often just as complex, are produced by the so-called striking mechanism.

Basic operating principles

The basis of every time display is always a physical or chemical process that proceeds as uniformly as possible. To do this, a certain amount of energy must always be used or supplied. The visible change in the arrangement used for display is a second aspect that is independent of the principle.

A distinction can be made between analog and digital processes. “Digital” here in the sense of step-by-step processes, composed of separate, countable individual events.

Analog time measurement processes are, for example, the apparent wandering of the sun around the earth (exploited in the sundial), the burning of candles, the steady draining or running of water from or into a container.

Digital time measurement processes are, for example, pendulum oscillations (pendulum clocks), rotary pendulum oscillations (wristwatches), oscillations of a tuning fork (first electronic clocks), oscillations of an oscillating quartz (quartz watch) or oscillations of separate atoms (atomic clock). In mechanical clocks, the pendulum oscillations are used to slow down the rapid and steady movement of the spring or the weights through the escapement in small (digital) time steps, which then have to be counted. Especially with large clocks, the resulting jerky movements of the hands are directly visible. Generally, prior to getting one expiring in strictly constant time intervals process that counted is or is countable. (In this sense, radio clocks are pure display units and, when measuring the time, go back to the atomic clock that controls the time transmitter.)

The display dissipate in hours, minutes and seconds from these basic operations, is a separate, independent process. Mixed forms are often found, for example, in which the continuous burning of a candle is combined with digital (read: punctual) displays full of hours by melting metal balls into the candle at regular intervals, which then fall into a metal bowl when it burns and thus an audible acoustic signal to produce. Conversely, the actually digitally counted oscillations of a pendulum are converted into an (apparently) analog display on a dial using the escapement and a reduction .

Natural timers

Many biological organisms have mechanisms that control their behavior over the course of the day, especially the sleep / wake rhythm, see chronobiology .

In genetics , the statistical natural mutation frequency , e.g. B. in determining the timing of the formation of a new species or subspecies , referred to as the molecular clock .

Radiocarbon dating uses the effects of constant processes to determine very large periods of time (years to hundreds of millions of years) . Processes that occur periodically in nature, such as annual rings, are used in dendrochronology to determine the age of wood . In a figurative sense, the slowly occurring changes are geological or biological "clocks".

More terms

literature

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  • The world as a clock. German clocks and automata 1550–1650. Edited by Klaus Maurice and Otto Mayr. Exhibition catalogs Bavarian National Museum, Munich 1980.
  • Silvio A. Bedini: The mechanical clock and the scientific revolution. In: The world as a clock. German clocks and automata 1550–1650. Edited by Klaus Maurice and Otto Mayr . Exhibition catalog Bayerisches Nationalmuseum, Munich 1980, pp. 21–29.
  • David S. Landes : Revolution in Time. Clocks and the Making of the Modern World. WW Norton, New York 1983 (also at Harvard University Press, Cambridge / Mass. / London 1983).
  • Jürgen Abeler : Time signs. The portable watch from Henlein to this day. Harenberg Kommunikation, Dortmund 1983, ISBN 3-88379-362-0 .
  • Z. Martinek, J. Rehor: Mechanical watches. 5th edition. Berlin (East) 1983.
  • Jean-Marc Barrelet: Petit Guide pour servir à l'Histoire de l'Horlogerie. Neuchâtel 1988.
  • Gisbert L. Brunner : Watches with a soul. In: Lui. No. 12, 1988, pp. 48-51.
  • Gisbert L. Brunner: Golden times for timepieces on the wrist. In: clocks. No. 5, 1989, pp. 45-54.
  • Klaus Menny : The function of the clock. Munich 1989.
  • Rudi Koch (Ed.): BJ-Lexikon. Clocks and timekeeping. 2nd edition, Leipzig 1989.
  • Gerhard Dohrn-van Rossum : The story of the hour. Clocks and modern time systems. Hanser, Munich 1992, ISBN 978-3-446-16046-0 ; Reprint Anaconda, Cologne 2007, ISBN 978-3-86647-139-9 .
  • Jürgen Abeler: Ullstein clocks book. A cultural history of time measurement. Ullstein, Frankfurt am Main 1994, ISBN 3-550-06849-2 .
  • Victor Pröstler: Callweys manual of the clock types. Munich 1994.
  • Gerhard Claussen, Karl-Hermann: The great ABC of clocks. 2nd Edition. Bremen 1996.
  • Giampiero Negretti, Paolo De Vecchi: The fascination of clocks. Munich 1996.
  • Gerhard König: The clock. History, technology, time. Koehler + Amelang, Berlin 1999, ISBN 3-7338-0065-6 .
  • Carlo M. Cipolla: Counted time. How the mechanical watch changed life. Wagenbach, Berlin 1999, ISBN 3-8031-2343-7 .
  • Lambert Wiesing: The clock. A semiotic view . Issue 5. St. Johann GmbH, Saarbrücken 1998, ISBN 3-9285-9633-0 .
  • Harry M. Vehmeyer: Clocks. Their origin and development 1320-1880. Ghent 2004.
  • Gerhard Dohrn-van Rossum, Marcus Popplow: clock, clockmaker. In: Encyclopedia of Modern Times. Volume 13: Subsistence farming - vassal. Stuttgart 2011, Col. 887-896.

Web links

Wiktionary: Uhr  - explanations of meanings, word origins, synonyms, translations
Commons : Clocks  - collection of pictures, videos and audio files
Wikiquote: Clock  - Quotes

Individual evidence

  1. ^ Friedrich Kluge , Alfred Götze : Etymological dictionary of the German language . 20th edition, ed. by Walther Mitzka , De Gruyter, Berlin / New York 1967; Reprint (“21st unchanged edition”) ibid 1975, ISBN 3-11-005709-3 , p. 801.
  2. ↑ Gr. σκάφη skáphē , "deceit", probably so called because the sundial was usually concave, cf. Verbal root σκαπ - / - σκαφ- [* skap - / - skapʰ-], "dig".
  3. ↑ See naming of some alpine mountains: z. B. Mittagshorn , Mittagsplatten , Zwölfihorn ; Jakob Messerli: Evenly. In time. Fast. Time division and use of time in Switzerland in the 19th century . Chronos, Zurich 1995, ISBN 3-905311-68-2 .
  4. ^ Chamber of Crafts Koblenz, State Museum Koblenz: Masterpieces. 2000 years of craftsmanship in the Middle Rhine. Volume 8: Watches, Koblenz 1992, ISBN 3-925915-38-9 .
  5. ↑ E.g. the geared odometer of the Heron of Alexandria (around 100 BC)
  6. ↑ The term watchmaker was mentioned for the first time in 1269 on a beer bill for the Beaulieu monastery.
  7. ^ Gerhard Dohrn-van Rossum: The story of the hour. Clocks and modern time systems. Anaconda, Cologne 2007, ISBN 978-3-86647-139-9 , p. 157.
  8. ↑ Reinhard Meis: The old clock. Vol. 1. Klinkhardt & Biermann, Braunschweig 1978, ISBN 3-7814-0116-2 , p. 77 ff.
  9. ↑ Frederick Kaltenböck, Die Wiener Uhr […]. Callwey, Munich 1988, ISBN 3-7667-0899-6 .
  10. ↑ The oldest verifiable wooden tower clock was built in 1377 in the Belfry of Ghent . A. van Werveke from the archives of the Reich Archives in Brussels, 1928.
  11. ^ Berthold Schaaf: wooden wheel clocks. Callwey, Munich 1986, ISBN 3-7667-0791-4 .
  12. ^ Alfred Beck: Neither real nor fake? A contribution to the consideration of the so-called Burgundy clock. In: The clock. Trade magazine for the watch, jewelry u. Silver merchandise management. Volume 3, 1959, pp. 20-22.
  13. ^ Ernst von Bassermann-Jordan : The grandfather clock of Philip the good of Burgundy. Leipzig 1927.
  14. ↑ Max Engelmann: The Burgundy spring clock around 1430. Halle an der Saale, 1927.
  15. ^ Helmut Kahlert , Richard Mühe , Gisbert L. Brunner : Wristwatches: 100 years of development history. Callwey, Munich 1983; 5th edition, ibid 1996, ISBN 3-7667-1241-1 , p. 10.
  16. ^ Samuel Guye, Henri Michel: Clocks and measuring instruments of the 15th to 19th centuries. Orell Füssli, Zurich 1971.
  17. ↑ Proof of these clocks in the Vienna Art History Museum and in the J. Fremersdorf collection in Lucerne.
  18. ↑ Fritz von Osterhausen: Callweys lexicon. Callwey, Munich 1999, ISBN 3-7667-1353-1 , p. 16.
  19. ↑ Helmut Kahlert: 300 years of the Black Forest watch industry . Katz, Gernsbach 2007, ISBN 3-938047-15-1 .
  20. ^ JD Weaver: Electrical & Electronic Clocks & Watches. London 1982.
  21. ^ Gisbert L. Brunner: wrist watches. Heyne, Munich 1996, ISBN 3-453-11490-6 , p. 16 ff.
  22. ^ Gisbert L. Brunner: wrist watches. Heyne, Munich 1996, ISBN 3-453-11490-6 , p. 30 ff.
  23. ^ BIPM - International Atomic Time. In: bipm.org. Retrieved July 25, 2011 .
  24. ↑ A pendulum clock , partly working in a vacuum , with an accuracy of one tenth of a second per day. Spectrum of Science: Special-ND1 , 2007: Phenomenon Time, p. 35.
  25. ^ Helmut Kahlert , Richard Mühe , Gisbert L. Brunner : Wristwatches: 100 years of development history . Callwey, Munich 1990; 5th, expanded edition, ibid. 1996, ISBN 3-7667-1241-1 , p. 7.
  26. ^ Helmut Kahlert , Richard Mühe , Gisbert L. Brunner , Christian Pfeiffer-Belli: wrist watches: 100 years of development history. Callwey, Munich 1983; 5th edition, ibid. 1996, ISBN 3-7667-1241-1 , p. 505 ( Complicated wristwatch ).
  27. ^ Bassermann / Bertele: clocks. Klinkhardt & Biermann 1961, p. 165 f.
  28. ^ Bassermann / Bertele: clocks. Klinkhardt & Biermann 1961, p. 159 f.
  29. ^ Gisela Teichmann: William Harvey and the cardiac output. In: internal medicine. Volume 19, 1992, No. 3, pp. 94-96, here: p. 95.
  30. ^ Georg Küffner: About the Qlocktwo by Marco Biegert and Andreas Funk in FAZ, April 19, 2010.
  31. ↑ Clock hands from Hamburg church crashed orf.at, October 17, 2016.