Clock Dictionary

7/27/2019 Clock Dictionary

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Alarm:Mechanical function serving as a wake-up alarm or a reminder of an event or appointment. Created in 1950,

the line of Jaeger-LeCoultre Memovox, literally voice of memory alarm watches made its mark on

watchmaking history, giving rise to a number of world firsts.

Assembly:After being made and decorated in the many different Jaeger-LeCoultre workshops, the parts of each watch

movement are assembled by the watchmakers, who then proceed to adjust them.

Atmos:Invented in 1928, this almost perpetual clock by Jaeger-LeCoultre is rewound by infinitesimal changes in

temperature. For over half a century, it has been the Swiss governments official gift to its most prestigiousguests.

Automatic calibre:Calibre equipped with an oscillating weight that automatically winds the watch when it is worn on the wrist.

Automatic movement:Movement equipped with an oscillating weight ensuring automatic winding of the watch when it is worn.

Balance:Circular component which is made to oscillate at a cadence corresponding to the ticking rhythm of the watch.

Jaeger-LeCoultre has developed a balance fitted with small adjustable inertia-blocks and referred to as avariable-inertia balance.

Balance-spring:Tiny spring boasting excellent resistance and elasticity, fixed to the balance. Its return force drives the balance

oscillations. To optimise the precision of the Reverso Gyrotourbillon 2, Jaeger-LeCoultre equipped it with acylindrical balance-spring

Barrel:Set of components (drum, arbor, mainspring and cover) serving to store up the energy required to power the

watch. Jaeger-LeCoultre wristwatches may be endowed with up to 15 days power reserve.

Calibre:Movement model. Each calibre results from a development process that may last several years. Jaeger-

LeCoultre has 1,000 different calibres in its range, of which more than half are equipped with complications.

Case:Element intended to contain and protect the watch movement. The case of a Jaeger-LeCoultre Reverso

comprises at least 50 parts ensuring its water resistance, its sturdiness and a perfect swivel.

Chronograph:Classic horological complication serving to measure a duration and characterised by start, stop and reset

functions. Jaeger-LeCoultre has created around 200 chronograph calibres, several of which are endowed with

the split-second function.

Chronometer:High-precision watch. The first chronometers were created for the navy to determine longitude. Throughinventions such as the cylindrical balance-spring, the isometer escapement and the variable-inertia balance,

Jaeger-LeCoultre perpetuates the quest for precision, duly certified by the 1000 Hours Control test.

Clous de Paris:Traditional hobnail type decorative pattern created using the guilloch or engine-turned technique.

Column wheel:High-quality component of chronograph watches serving to alternate between the START and STOP

functions. All Jaeger-LeCoultre chronograph watches are equipped with a column wheel.


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Complication:Horological mechanism enabling a timepiece to provide indications in addition to the time of day, or endowing

the watch with a superior degree of precision or sophistication. Jaeger-LeCoultre has created over 500 calibres

equipped with complications since 1833, including more than 200 repeaters, over 190 chronographs and

several high complications.

Compression key:The patented Jaeger-LeCoultre compression key replaces the traditional screw-lock crown and ensures optimal

water resistance. A device serves to secure the crown so as to better protect the watch movement. The

compression key gave rise to the Master Compressor line created in 2002.

Coupling clutch:Device linking the chronograph mechanism to the movement and enabling the user to start or stop time

measurements. The Duomtre Chronographe is the only watch that requires no coupling clutch to activate the

chronograph.

Cradle or carrier:Fixed part of the Reverso watch serving to fix the wristband and as a support or base for the watch to swivel.

The first watch with three dials, the Reverso grande complication triptyque uses the two sides of the watch as

well as its cradle, which houses a perpetual calendar.

Crown:Mobile element linking the outside of a watch to its mechanism and serving to rewind the watch, set it to timeor adjust its functions. In 1847, Antoine LeCoultre developed a lever-based crown winding system that freed

the watch from the need for a key.

Depth gauge:Function enabling divers to check their current depth. The mechanical depth gauge developed by Jaeger-LeCoultre uses an hermetic membrane ensuring gasket-free watertightness and thus enabling peerless

precision.

Dial:Part bearing the time indications: hours, minutes, seconds, date, month, etc Jaeger-LeCoultre has created thefirst watch in watchmaking history equipped with three dials driven by a single movement: the Reverso grande

complication triptyque

Dual-Wing:New mechanical movement concept developed by Jaeger-LeCoultre to equip the Duomtre watch line. Twoindependent gear trains with their own source of energy are synchronised by a single regulating organ, thus

guaranteeing complicated watches a chronometer-worthy level of precision.

Duoplan:Invented in 1925, the Duoplan watch solved the issue of the precision of tiny watches by arranging themovement parts on two levels. Its smallest version is equipped with Calibre 101, which has remained the

worlds smallest mechanical watch movement since 1929.

Elinvar:Alloy impervious to changes of temperature, invented by the Swiss Nobel prize-winner Charles-EdouardGuillaume (1861-1938). Inside each Atmos clock, a very large balance oscillating once a minute is suspended

from an extremely fine elinvar wire. Jaeger-LeCoultre has developed a secret technology that enables Elinvar

wire to last for centuries.

Ellipse isometer escapement:Developed by Jaeger-LeCoultre, this highly sophisticated and exceptionally accurate escapement is inspired by

the escapements developed in the 18th and 19th centuries for marine chronometers.


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Enamelling (miniature):Decorative technique applied to the cases of the most prestigious timepieces since the 17th century. The

wristwatch almost caused the extinction of this time-honoured know-how. Jaeger-LeCoultres miniature

enamelling studio is one of the only centres of expertise perpetuating this pictorial art.

Equation of time:Difference between civil or conventional time (indicated by the watch) and true time (indicated by the position

of the sun). The Gyrotourbillon I watch by Jaeger-LeCoultre features a running equation of time, a

complication that indicates not only the difference between these two times, but also their relative positions.

Escapment:Set of parts serving to transform the linear energy supplied by the mainspring into alternating energycorresponding to the ticking of the watch. The escapement guarantees the precision of the watch. Jaeger-

LeCoultre has been making its own escapements since the 19th century.

Folding clasp:Articulated metal part serving to ensure secure opening and fastening of the watch wristband. The first folding

clasp patent was filed by Edmond Jaeger in 1909. Several current models feature wristbands with double

folding clasps.

Frequency:Number of vibrations during a given period. The frequency of a watch is one of the key elements in itsprecision. The standard set by the Manufacture for its wristwatches ranges between 21,600 and 28,800vibrations per hour. While the Atmos by Jaeger-LeCoultre features one of the lowest frequencies in the watch

industry (60 vibrations per hour), careful adjustment can enable it to achieve chronometer-worthy precision.

Futurematic:Created in 1953, the Futurematic watch by Jaeger-LeCoultre was the first fully automatic wristwatch inwatchmaking history, since it could do without a winding crown. It stored up enough energy to restart with

great accuracy, even after a long period of inactivity.

GMT:Greenwich Mean Time. Reference time adopted in the 19th century to define the worlds different time zones.The Reverso Grande GMT by Jaeger-LeCoultre indicates, in addition to the two time zones, the difference

between the second time zone and GMT.

Gem-set engraving:Technique used to personalise the back of Reverso watches and combining engraving with gem-setting. Increating a gem-set engraving, the engraver performs 19 successive operations.

Geophysic (chronometer):Antimagnetic model created in 1958 for scientists taking part in the International Geophysical Year. The

Geophysic Chronometer by Jaeger-LeCoultre was presented to the commander of the Nautilus, the first everatomic submarine, after its passage beneath the North Pole.

Gong:Component used to emit a sound when struck by a hammer. The art of making minute repeater gongs is one of

the most delicate in the watch trade. To optimise the quality of the sound, the gongs of the Master MinuteRepeater are fixed to the sapphire crystal which protects the watch dial.

Grande Complication:A "grande complication" watch is equipped with at least three classic complications. In the 1890s, the first

grand complication watches by Jaeger-LeCoultre featured a perpetual calendar, a minute repeater and a

chronograph


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Grande Maison:Nickname given to Jaeger-LeCoultre since the 19th century in the Valle de Joux. The first full-fledged

watchmaking manufacturer in the region, it had a workforce of almost 500 by the late 1880s.

Guard-pin or dart:This small metal pin is located beneath the lever and serves to protect the watch escapement from violent

impacts. The dart of Jaeger-LeCoultre Calibre 101 weighs just 0.00017 grams.

Gyrotourbillon:Spherical tourbillon developed by Jaeger-LeCoultre, composed of a double tourbillon carriage spinning on two

axes. Highly sophisticated complication designed to enhance the precision of the watch in all positions. The

Gyrotourbillon comprises around a hundred parts weighing a total of less than one-third of a gram.

Hammer:Part used in striking or alarm watches to hit the gongs. Invented by Jaeger-LeCoultre, the so-called trbuchet

(assay balance) hammer is articulated in such a way as to optimise energy transmission.

Hanging gong:Metal component used in Jaeger-LeCoultre alarm watches since 1989 to enhance the sound quality of the

alarm. Previous Memovox watches were equipped with hammers directly striking the inside of the watch case.

Hometime:Concept developed for frequent travellers. This mechanism displays as its main function the second time zone,adjustable by simply pressing a pushpiece. The time in the first time zone (Hometime) is indicated by means of

a hand positioned in the background.

Integrated design:Concept according to which the creation of a product must incorporate its appearance as well as its contents, itstechnology, its functions and its user-friendliness. At Jaeger-LeCoultre, calibres are developed simultaneously

with watch cases, each tailored to the other so as to guarantee product integrity and fully integrated design.

International Timing Competition:The Chronometrie 2009 international timing competition for mechanical wristwatches was held to mark the50th anniversary of the watch museum in Le Locle. This watchmaking town in Canton Neuchtel, Switzerland,

was known in the pre-quartz-watch era for its chronometers. It was the first timing competition since theNeuchtel observatory held the last trial in 1972. A Jaeger-LeCoultre Master Tourbillon Calibre 978

wristwatch has won the first timing competition in more closely followed in second place by the Reverso

Gyrotourbillon 2 (Jaeger-LeCoultre ) Calibre 174.

Jaeger Edmond (1851-1922):French chronometer-maker who set up in Paris in 1880. His cooperation with LeCoultre &Cie began in 1903with the creation of ultra-thin calibres, and led to the creation of the Jaeger-LeCoultre brand in 1937.

Jewel:To limit the wear engendered by the friction of metal components within a watch, watch jewels are placed in

the most sensitive parts of the mechanism. Originally, watch jewels were genuine rubies such as those used injewellery. They were subsequently replaced by artificial stones in red corundum, which are both purer and

more resistant. Jumpind seconds:

Hand performing a complete rotation in one second with several intermediate stops. The jumping seconds handon the Duomtre Chronographe by Jaeger-LeCoultre serves to measure sixths of a second.

Jumping-hand date:Mechanism serving to indicate the date by means of a hand. The date hand of the Master Tourbillon makes a

bigger jump between the 15th and the 16th so as not to hide the tourbillon from view.


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Lacquered engraving:Technique used to personalise the back of Reverso watches. After hollowing out the matter, the engraver fills

in the hollows using different-coloured lacquers.

Large date:Calendar-type horological complication serving to enhance the readability of the date. The patented Jaeger-

LeCoultre large date uses two discs: one for units and the other for tens.

LeCoultre Antoine (1803-1881):Founder of the Manufacture Jaeger-LeCoultre. A brilliant inventor, he created the first workshop of the

Manufacture in 1833 following his invention of a watch pinion-cutting machine.

Lever:An essential organ in ensuring the accuracy of a watch and which, by alternating movements, releases the

energy required to drive the mechanism. For over a century, Jaeger-LeCoultre has been one of the only watch

companies to produce its own leverswhich have indeed inspired the brand logo.

Line engraving:Engraving performed using a burin that hollows out the matter. The technique most frequently used by the

Jaeger-LeCoultre engravers to personalise the back of Reverso watches.

Manually-wound calibre:Calibre requiring manual winding by the crown. Depending on the model, Jaeger-LeCoultre manually-woundwatches need to be wound once a day, once a week or once every two weeks.

Manually-wound movement:Movement requiring manual winding by means of a crown. Depending on the model, Jaeger-LeCoultre

manually-wound watches must be wound once a day, once a week or once every two weeks.

Manufacture:Within the watch industry, the French term Manufacture in its strictest sense implies the regrouping beneath

one roof of all the skills required to design and make watches from A to Z. Jaeger-LeCoultre encompasses over

40 different professions and 20 cutting-edge technologies serving to transform the most ambitious inventionsinto exceptional timepieces.

Memovox :Famous line of alarm watches created in 1950 by Jaeger-LeCoultre and literally meaning the voice of

memory. In 1956 the line was enriched by the first ever automatic alarm watch. Three years later, theMemovox Deep Sea was the first divers watch to be equipped with an alarm.

Micron:Unit of measurement representing one thousandth of a millimetre. Invented in 1844 by the founder of Jaeger-

LeCoultre, the Millionometer was the first instrument in the history of technologies capable of measuringmicrons.

Millionometer:Invented in 1844 by Antoine LeCoultre, the Millionometer was the first measuring instrument in the history of

technologies capable of measuring microns. It contributed to the conquest of precision and reliability.

Minute Repeater:Highly sophisticated horological complication serving to provide, upon demand and at any time, a coded

audible indication of the time in hours, quarter-hours and minutes. Repeater watches were invented before

electricity in order to tell the time in the dark. Jaeger-LeCoultre has created over 200 different repeatercalibres.


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Modelled engraving:Applied to the back of Reverso watches, this sculpture-like engraving technique consists in creating genuine

miniature bas-reliefs. It calls for considerable manual dexterity.

Moon phase:Indication serving to display the moon phases at any given time. The Atmos is equipped with a perpetual

moon-phase indicator that will show a one-day discrepancy only once in 3,821 years.

Nickel silver:A silvery-looking copper, nickel and zinc alloy widely used in the 19th century and now reserved by Jaeger-

LeCoultre for some of its movements equipped with complications.

Oscillation:To-and-fro swinging motion of the balance, resulting in the characteristic ticking of a watch. One oscillation (a

complete to-and-fro swing of the balance) corresponds to two vibrations (movement of the balance in one

direction and then the other).

Perpetual calendar:Classic horological complication serving to display one or several calendar indications (date, day, month, year,

moon phase) by taking account of the variable lengths of months with 28, 29, 30 and 31 days, thus including

those determined by the leap-year cycle. Jaeger-LeCoultre has been making perpetual calendar movementssince the 1890s.

Pinion:Central component of a moving part, generally in hardened steel and toothed. The first Jaeger-LeCoultre

workshop was created in 1833 following the invention of a revolutionary watch pinion-cutting machine. It

marked the start of the integration of all watchmaking skills beneath one roof.

Polaris:Shorter version of the name for the Memovox Polaris, the famous divers watch created by Jaeger-LeCoultre in

1965 and fitted with a triple case-back enhancing the underwater diffusion of the alarm sound. Created in

2008, the Memovox Tribute to Polaris is a reinterpretation of the original model.

Power reserve:Time that elapses between when a watch is fully wound and when it comes to a stop. Some watches indicatethe remaining autonomy of the watch through an aperture or by means of a pointer. While some Jaeger-

LeCoultre watches can boast up to two weeks of autonomy, the Atmos clock is designed to run forever.

Pushpiece:Element connecting the case to the movement and serving to start or stop various watch functions such as the

chronograph for the time-zone displays. Jaeger-LeCoultre calendar watches are equipped with a pushpiecewhich serves to simultaneously move forward all the different calendar functions: day, date, month, moon

phases and years.

Reverso:Invented in 1931 to meet a challenge set by British colonial army officers stationed in India and who wanted awatch capable of surviving a polo match. Its brilliant swivel and its inimitable style made the Reverso a grand

Art Deco classic. It is currently one of a rare circle of genuinely iconic watch models. Rotor:

Driven by wrist movements, the rotor (or oscillating weight) winds the watch mechanism so as to ensure itsautonomy. A watch equipped with a rotor is referred to as automatic or automatic-winding.

Running solar time:Mechanism serving to check solar time or true time (based on the position of the sun) at any time, as opposed

to civil, standard or conventional time (annual mean solar time). The Gyrotourbillon I features a running solartime indication.


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Rtrograde:Refers to a mechanism serving to bring a hand back to its starting point after running over part of the dial. The

perpetual date of the Gyrotourbillon I watch by Jaeger-LeCoultre features two retrograde hands.

Sapphire crystal:Extremely resistant and perfectly transparent crystal used as a watch glass. Jaeger-LeCoultre was one of the

pioneers of sapphire crystals, since it began equipping the Duoplan and Reverso watches with them in the early

1930s.

Shaped calibre:Calibre featuring any shape other than a circle, such as those used by Jaeger-LeCoultre for the legendary

Reverso watch.

Shock absorber:Component serving to dampen shocks sustained by the watch in order to protect the mechanism. All modern

Jaeger-LeCoultre watches are equipped with shock-absorbing systems. The world-first Extreme case by

Jaeger-LeCoultre absorbs 50% of the energy generated by impacts and vibrations.

Skeleton(ised) or openworked:Refers to a movement from which all or part of the non-functional matter has been removed in order to create

an effect of stunning transparency. Skeletonising or openworking is a hand-crafted operation performed by thefinest artisans.

Small seconds:Display of the seconds on a subdial, often positioned at 6 oclock. In the 19th century, most of the pocket-

watches equipped with LeCoultre calibres featured a small seconds indication.

Snow setting:Technique developed by Jaeger-LeCoultre that consists in setting a given surface with diamonds of varying

diameters, in such a way as to entirely cover the metal and create an extraordinary sparkling effect. Each watch

set using this technique is truly unique, since the arrangement of the diamonds is redefined in each case by the

jewellery craftsman according to the diamonds at his disposal and his personal inspiration.

Soleillage:Decoration developed by Jaeger-LeCoultre to embellish its mechanical movements. Soleillage, or ctessoleilles are created by modifying the surface of a part using a grinding wheel that creates lines radiating out

from a given centre, somewhat like the rays of the sun (hence the French name referring to a sunny effect).

Split-second function:Split-second chronographs are equipped with two superimposed seconds hands, one of which can be stopped at

will to show a split time, before catching up with the first hand. Jaeger-LeCoultre has created over 60 calibresequipped with the split-second function.

Spring torque indicator or torquemeter:Indicates the force available in the barrels. A system developed by Jaeger-LeCoultre in 2005 for the Master

Minute Repeater.

Tourbillon:Classic horological complication serving to compensate for the effects of gravity on the precision of a watch.All parts of the regulating and distributing organs are incorporated within a carriage that spins on its axis,

generally at the rate of once every 60 seconds.

Tourbillon regulator:Classic horological complication serving to compensate for the detrimental effects of gravity on the precision

of a mechanical watch. The balance is incorporated within a so-called tourbillon carriage that spins on its

axis, generally at the rate of once a minute.


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Ultra-thin:In watchmaking, extremely thin movements are considered to be one of the most demanding specialities. In

1907, Jaeger-LeCoultre Calibre 145 set a world record at just 1.38 thick. Subsequently produced for over half a

century, it repeatedly confirmed its reliability and gave rise to a prestigious line of movements.

Valle de Joux:Valley located at an altitude of 1,000 metres in the Swiss Jura region, distinguished by its geographical

isolation and its specialisation in horological complications since the 18th century. Jaeger-LeCoultre has been

known as the Grande Maison in the Valle de Joux since the 19th century.

Vertical-trigger chronograph:This patented Jaeger-LeCoultre mechanism serves to start, stop and rest the chronograph by simply pressing onthe sapphire watch crystal.

Vibration:Movement of the balance in one or the other direction, resulting in the characteristic ticking sound of a watch.

Most Jaeger-LeCoultre watches beat time at a rate of 28,800 vibrations per hour, thus guaranteeing optimal

precision. Two vibrations make up one oscillation.

Winding mechanism:Mechanism serving to wind the watch and set it to time. Winding mechanisms originally served exclusively totauten the mainspring of watches. In 1847, Antoine LeCoultre created the first reliable system combining both

these functions.

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