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Remontoire
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In mechanical horology, a remontoire (from the French remonter, meaning 'to wind') is a small secondary source of power, a weight or spring, which runs the timekeeping mechanism and is itself periodically rewound by the timepiece's main power source, such as a mainspring. It was used in a few precision clocks and watches to place the source of power closer to the escapement, thereby increasing the accuracy by evening out variations in drive force caused by unevenness of the friction in the geartrain. In spring-driven precision clocks, a gravity remontoire is sometimes used to replace the uneven force delivered by the mainspring running down by the more constant force of gravity acting on a weight. In turret clocks, it serves to separate the large forces needed to drive the hands from the modest forces needed to drive the escapement which keeps the pendulum swinging. A remontoire should not be confused with a maintaining power spring, which is used only to keep the timepiece going while it is being wound.
How it works
[edit]Remontoires are used because the timekeeping mechanism in clocks and watches, the pendulum or balance wheel, is never isochronous; its rate is affected by changes in the drive force applied to it. In spring-driven timepieces, the drive force declines as the mainspring runs down. In weight-driven clocks the drive force, provided by a weight suspended by a cord, is more constant, but imperfections in the gear train and variations in lubrication also cause small variations. In turret clocks, the large hands, which are attached to the clock's wheel train, are exposed to the weather on the outside of the tower, so winds and accumulations of ice and snow apply disturbing forces to the hands, which are passed on to the wheel train.
With a remontoire, the only force applied to the clock's escapement is that of the remontoire's spring or weight, so that it is isolated from any variations in the main power source or wheel train, which is just used to rewind the remontoire. Remontoires are designed to rewind frequently, at intervals between one second and an hour. The rewinding process is triggered automatically when the remontoire's weight or spring reaches the end of its power. This frequent rewinding is another source of accuracy, because it averages out any variations in the clock's rate due to changes in the force of the remontoire itself. If the rate of the clock varies as the remontoire spring runs down, this variation will be repeated again and again, each time the remontoire goes through its cycle, so it will have no effect on the long term rate of the clock.[1]
History
[edit]The gravity remontoire was invented by Swiss clockmaker Jost Bürgi around 1595. Usually the "Kalenderuhr" (three month running, springdriven, calendar-desk-clock) Bürgi[clarification needed] is considered the oldest surviving clock with a remontoire, even if it does not provide power to the escapement during the few seconds of the daily cycle where the remontoire weight gets wound up by the spring.[2] Today remontoire mechanisms are all designed to deliver power to the escapement during the remontoire reset cycle.
The spring remontoire was invented by English clockmaker John Harrison during development of his H2 marine chronometer in 1739. Harrison's working drawing of the device is preserved in the Library of the Worshipful Company of Clockmakers in London, England.[3]
Many French and Swiss pocketwatches after 1860 were stamped on the back with the word Remontoire. This merely meant that they didn't have to be wound with a key (i.e. they were wound by the then-novel winding crown inside the pendant). Etymologically the term is correct, the mainspring is "rewound" by some other force than a key, but these watches usually do not contain a remontoire as the word is used today.[4]
Types
[edit]Remontoires are distinguished by their power source:
- A gravity remontoire is one that uses a weight for power. It is used in precision pendulum clocks.
- A spring remontoire uses a spring. It is the only type which can be used in watches, since the force of a weight would be disturbed by motions of the wearer's wrist
- An electric remontoire can be either a gravity or spring type. In it, the weight or spring is rewound electrically, with a motor or solenoid. It is used in clocks with traditional mechanical movements which are run on electricity.
They can also be classified by where in the wheel train the remontoire is located:
- An escapement remontoire applies its force directly to the escape wheel of the escapement. Spring remontoires were usually of this type.
- A train remontoire applies its force to one of the wheels upstream from the escapement, usually to the wheel that drives the escape wheel.
Electric remontoires in automobile clocks
[edit]
Before the common use of electronic clocks in automobiles, automobile clocks had mechanical movements, powered by an electric remontoire. A low power drive spring would be wound every few minutes by a plunger in a solenoid, powered by the vehicle's service battery and activated by a switch when the spring tension got too low. Such clocks were, however, notoriously inaccurate, typically being made as cheaply as possible.
Many Rover (P4 to P6), Ford (Mk1 Escort, Mk2 Cortina, and Mk1 Capri GT/RS), and Triumph (Dolomite, 2000/2500, and Stag), as well as some Jaguar (S3 E-type), Daimler (DS420), and Aston Martin (V8) cars were fitted with Kienzle clocks that were wound by such electric remontoires.
Footnotes
[edit]- ^ "Clocks". Encyclopædia Britannica, 11th Ed. Vol. 6. The Encyclopædia Britannica Co., Cambridge. 1910. Retrieved 2008-06-08. p.543-544
- ^ Karsten Gaulke: Der Ptolemãus von Kassel; Kassel: 2007; ISBN 978-3-931787-43-1, Page 143
- ^ "Mechanical Notes and Drawing Compiled by John Harrison and his son William c.1726-1772", p.13
- ^ Fried, Henry B. (July 1995). "What is a remontoire?". Modern Masterpieces of Horology. Heritage, Jeweler's Circular Keystone, Cahner's Business Information. Archived from the original on 2006-06-28. Retrieved 2008-06-23.
External links
[edit]Remontoire
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Fundamentals
Definition and Purpose
A remontoire, derived from the French term "remontoir d'égalité," is a secondary power transmission mechanism in mechanical horology that delivers a consistent, impulse-like force to the escapement, thereby isolating it from the variable torque produced by the mainspring or weight-driven power source.[3][2] This device functions as an intermediary energy reservoir, typically employing a small auxiliary spring or weight that is periodically recharged to maintain uniformity in power delivery.[4] The primary purpose of the remontoire is to compensate for the inherent decreasing power output of mainsprings—known as isochronism error—which causes variations in the oscillation rate of the balance wheel or pendulum, and to mitigate irregularities arising from long gear trains.[4][2] By ensuring the escapement receives uniform energy impulses, it promotes precise and stable timekeeping, particularly in mechanisms where accuracy is essential.[3] At its core, the remontoire addresses the basic challenge of uneven power delivery in mechanical timepieces: as the mainspring unwinds, its torque diminishes, leading to rate inconsistencies that degrade performance over time.[4] Acting as an equalizer, the remontoire periodically rewinds its auxiliary energy source to release measured, consistent forces, thereby sustaining optimal oscillations without direct influence from the primary power variations.[3][5] Spring and gravity variants exist to achieve this constant-force effect.[3] This mechanism was primarily developed for precision timepieces where accuracy is paramount, such as astronomical clocks used in scientific observations.[6]Advantages and Limitations
Remontoires offer significant advantages in enhancing the precision of timepieces by delivering a constant torque to the escapement, thereby improving isochronism and minimizing variations in the rate caused by fluctuating mainspring power.[7] This isolation of the escapement from irregularities in the gear train, such as friction or wear, supports stable timekeeping.[4] In precision clocks, these mechanisms contribute to marked improvements in rate consistency. Despite these benefits, remontoires introduce notable limitations due to their mechanical complexity, which elevates manufacturing costs and requires specialized expertise for assembly and adjustment.[4] The addition of components like auxiliary springs or weights creates potential new friction points, leading to minor energy losses that must be carefully managed to avoid undermining overall efficiency.[8] Furthermore, the auxiliary power source in a remontoire typically has a limited reserve, often requiring rewinding every few seconds or hours, which can complicate long-term operation in portable timepieces.[7] These trade-offs position remontoires as ideal for high-end or specialized horological applications, where the gains in chronometric performance justify the increased bulk, expense, and maintenance demands, but render them impractical for mass-produced watches.[4]Operating Principles
Mechanism of Constant Force
The remontoire achieves constant force by employing a small auxiliary energy reservoir—typically a coiled spring or suspended weight—that is intermittently replenished from the clock's primary power source, such as the mainspring or driving weight. This secondary reservoir isolates the escapement from the primary source's inherent torque variations, delivering energy in uniform discrete impulses to maintain steady oscillation of the balance wheel or pendulum. By operating within a narrow range of its power curve, the auxiliary source provides a consistent output, independent of the main power's state of wind.[1] The operational cycle proceeds in distinct steps. First, the primary power source advances the gear train to wind the auxiliary reservoir via a lever or pallet that engages at precise intervals. Second, the fully charged auxiliary reservoir then directly powers the escapement, imparting impulses until its energy is sufficiently depleted. Third, a trigger mechanism—often a stop wheel, cam, or lever—activates when the reservoir reaches a threshold, disengaging the escapement drive and initiating rewinding from the main source; this typically occurs at regular intervals, typically every 1 to 10 seconds depending on the design. The process then repeats, with the periodic replenishment effectively buffering fluctuations and ensuring averaged uniformity in force delivery over time.[2] At its core, the physics of force equalization relies on maintaining invariant torque at the escapement from the steady force of the auxiliary reservoir. This counters the primary mainspring's torque decay, which decreases as the mainspring unwinds and loses tension. The result is preserved isochronism, as the timekeeping element receives consistent amplitude without positional or gravitational perturbations amplified by variable input.[4] Energy transfer efficiency stems from the remontoire's role as an intermediary buffer, which minimizes impulse variability by localizing power delivery near the escapement and reducing cumulative friction losses across the gear train. Each impulse is calibrated to match the exact energy needs of the balance or pendulum, with rewinding intervals optimized to avoid over-tensioning or slippage, thereby sustaining high precision while conserving overall power from the main source.[9]Key Components
The remontoire assembly consists of several core components that work together to deliver a consistent force to the escapement. The auxiliary spring or weight serves as the primary energy storage element, providing a short-duration reserve of constant force isolated from the mainspring's varying torque.[2] In spring-based designs, this is typically a coiled or bladed spring, while gravity types employ a falling weight on a lever arm. The winding lever or pallet transfers energy from the main gear train to rewind the auxiliary source at regular intervals, often every few seconds to minutes depending on the design.[2] The release trigger or detent regulates the precise timing of the auxiliary source's discharge, ensuring impulses are delivered at fixed intervals to maintain uniformity. This component, such as a stop wheel or jeweled pallet, prevents premature release and synchronizes with the escapement cycle. The escape wheel interface, usually a dedicated remontoire wheel or cage, directly transmits the stored force as impulses to the balance wheel or pendulum, minimizing variations in drive torque.[2] Variations in the remontoire assembly include its integration with the main gear train via a dedicated remontoire bridge, which supports the pivoting elements and maintains alignment. Jewels, typically synthetic ruby, are employed at pivot points to reduce friction and wear, with endstones capping high-pressure contacts. Assemblies scale in size for applications: larger configurations with heavier components suit tower clocks, while compact versions with finer tolerances fit pocket watches or wristwatches.[2][10] Material choices prioritize durability and precision. For auxiliary springs, high-elasticity alloys offer exceptional fatigue resistance, non-magnetic properties, and consistent performance under stress. The assembly is typically positioned adjacent to the escapement to shorten the power transmission path and limit losses, incorporating several additional wheels or gears for the winding and release functions. This setup ensures efficient energy isolation without overly complicating the overall movement.[11][12]Historical Development
Early Inventions
The concept of the remontoire originated in the late 16th century, primarily to mitigate the variability in force from mainsprings or weights in precision astronomical clocks, with initial designs focused on weight-driven systems to deliver consistent impulses to the escapement. This innovation addressed inconsistencies in power delivery caused by uneven winding or positional changes, enhancing overall timekeeping reliability.[2] Swiss horologist and astronomer Jost Bürgi developed the first gravity remontoire around 1580–1595, integrating it into his experimental clocks to provide steady drive through a small falling weight periodically rewound by the main gear train. Bürgi's mechanism, featured in pieces like his Experimental Clock No. 1, aimed to isolate the escapement from torque variations in the primary train, marking a foundational step in constant-force horology.[12][13] In the mid-17th century, Dutch physicist Christiaan Huygens advanced practical remontoire applications in his pendulum clocks from the 1650s onward, employing weight-driven designs to maintain uniform power during operation and winding, thereby reducing driving force fluctuations. These developments were spurred by pressing needs in astronomy for accurate celestial tracking and in navigation for reliable longitude determination at sea, with early prototypes tested in marine chronometers to endure shipboard motion and environmental stresses.[14][15] Despite their ingenuity, early remontoires suffered from significant limitations, including mechanical complexity that demanded exceptional craftsmanship and increased fragility, confining their use to elite scientific and navigational instruments rather than everyday clocks. The added components often raised costs and maintenance requirements, hindering broader adoption until later refinements.[12]19th and 20th Century Advancements
In the 19th century, remontoires saw key refinements that enhanced their reliability for precision timekeeping, particularly in large-scale applications. Abraham-Louis Breguet advanced spring-based remontoire designs, patenting a refined version in 1798 to provide more consistent force delivery to the escapement.[2] These improvements allowed for better integration with dead-beat escapements, reducing positional errors and improving overall accuracy in public and marine timepieces.[2] Edward John Dent further refined remontoire mechanisms during the mid-19th century, adapting them for tower clocks to ensure stable operation under varying loads. Dent's designs, patented in the 1850s, contributed to precision in notable public installations.[2][16] Harrison's original remontoire from his H4 marine chronometer also influenced 19th-century adaptations, with horologists refining the mechanism for broader use in chronometers to maintain constant force amid maritime conditions.[2] The 20th century marked a shift toward electric remontoires, which replaced mechanical winding with electromagnetic impulses for greater consistency. In the 1920s, Swiss firm A. Schild AG introduced the Electrora movement (French Patent FR621121, 1926), employing solenoids and pivoted armatures to periodically rewind the remontoire spring, enabling synchronous operation in automobile clocks.[17] This innovation addressed power variability in mobile applications, with similar systems patented in the 1930s for automotive use, such as those enhancing dashboard clock synchronization.[17] Industrial adoption expanded remontoires into standardized timekeeping, though mass production posed challenges due to the mechanisms' complexity and need for precise assembly. French inventor Paul Garnier's electric remontoires, evolving from his mid-19th-century self-winding designs, were deployed in master clocks for railroad stations and offices, distributing accurate time to slave dials and promoting schedule standardization across networks.[17] Post-World War II, firms like Schild advanced these with the Reform Calibre 5000 (Swiss Patent CH235319, 1945), facilitating miniaturization for wristwatches, though the rise of quartz technology in the 1970s led to a decline in mechanical and early electric variants.[17] A revival emerged in luxury horology after the quartz crisis, with independent makers reintroducing refined remontoires in high-end wristwatches for their constant-force benefits, as seen in George Daniels' 1975 tourbillon pocket watch.[2]Types of Remontoires
Spring Remontoire
The spring remontoire represents the most prevalent mechanical implementation of constant-force mechanisms in horology, employing a compact auxiliary spring to isolate the escapement from variations in the mainspring's torque. In its design, a small helical or spiral spring serves as the energy reservoir, periodically wound by a lever actuated from the main gear train, which transfers power to the escape wheel either through a fusee for gradual release or via a direct pallet for impulse delivery. This configuration ensures that the escapement receives a consistent driving force, mitigating the effects of uneven power delivery from the primary barrel. Functionally, the spring remontoire operates by rewinding the auxiliary spring at regular intervals, such as every second, 8 seconds, or longer, depending on the design, allowing it to discharge a measured portion of its stored energy with each cycle. The spring's tension adheres to Hooke's law, where the restoring force (with as the spring constant and as displacement) yields a nearly linear force-displacement relationship, translating to more uniform torque compared to the diminishing output of a mainspring alone. This periodic reset maintains the impulse to the escape wheel at a stable level, enhancing timekeeping precision over extended periods. The auxiliary spring provides power for the interval between rewinds, which can range from 1 second to a minute or more.[2] Key characteristics of the spring remontoire include its suitability for miniaturization, making it ideal for integration into portable timepieces where space constraints are paramount, though it introduces higher frictional losses relative to weight-based alternatives. While easier to fabricate at small scales, the mechanism demands precise calibration to minimize energy dissipation in the winding lever and arbor. Historically, spring remontoires gained prominence in 18th- and 19th-century pocket watches, where they were employed to improve accuracy in marine chronometers and high-end lever escapements. In contemporary horology, refined variants appear in tourbillon complications, such as those developed by watchmakers like Abraham-Louis Breguet's successors, to correct isochronism errors under varying amplitudes. These modern iterations often incorporate jeweled pivots and optimized spring materials to extend longevity, and continue to be used in high-end watches as of 2025.[2] Among its advantages, the spring remontoire excels in reliability for portable devices, offering a self-contained solution that withstands positional changes without relying on gravitational elements. However, a notable disadvantage is the potential for spring fatigue over time, which can lead to elastic hysteresis and diminished performance after years of operation, necessitating periodic maintenance or replacement of the auxiliary spring.Gravity Remontoire
The gravity remontoire employs a small falling weight or lever arm that is periodically rewound upward by the main gear train, delivering impulses to the escapement via the release of gravitational potential energy, expressed as , where is the mass of the weight, is the acceleration due to gravity, and is the height of descent.[12] This design isolates the timekeeping mechanism from irregularities in the primary power source, ensuring a more consistent drive.[18] In operation, the weight descends over a short arc to impart a constant force, with rewinding initiated by a tilt lever, pallet, or similar trigger at the end of its travel, often cycling every 30 seconds to one minute.[12] Such mechanisms are particularly adapted to pendulum clocks with periods of approximately 2 seconds, as seen in large-scale installations where steady, low-speed oscillations benefit from the even impulses.[19] Key characteristics include inherently low friction, achieved through gravity-driven motion without sliding contacts or lubrication in optimized forms, rendering it well-suited for substantial, stationary clocks like those in towers.[19] The system provides impulses at extended intervals—such as every pendulum swing—and its structural demands make it bulkier and impractical for portable timepieces.[12] The earliest known gravity remontoire dates to Swiss clockmaker Jost Bürgi's invention around 1595, featured in his experimental clocks.[12] By the 19th century, advancements like the double three-legged gravity remontoire escapement, perfected by Edward Denison in 1860, were integrated into astronomical regulators, including the mechanism for the Palace of Westminster clock (Big Ben).[19] This type offers advantages such as minimal component wear from the lack of elastic tensions and robust isolation of the escapement from environmental disturbances like wind or temperature shifts.[18] However, it introduces drawbacks including greater fragility, elevated production costs due to precision requirements, and the necessity for expert maintenance to sustain performance.[12]Electric Remontoire
The electric remontoire represents a hybrid approach in horology, integrating electrical components to deliver consistent impulses to a mechanical escapement, thereby isolating the timekeeping mechanism from variations in power supply. Unlike purely mechanical designs, it employs an electromagnet, solenoid, or moving coil system to periodically rewind a small auxiliary spring or directly provide timed pulses, ensuring a constant force delivery to the gear train and balance wheel. This design is particularly suited for compact applications such as automobile dashboards, where space constraints and the need for reliability without frequent manual intervention are paramount.[17] In operation, the electric remontoire functions by generating precise electrical impulses—typically every minute or synchronized to the clock's beat—to advance the escapement. A solenoid or electromagnet, powered by a low-voltage battery (such as 1.5V cells) or mains supply, attracts a pivoted armature or coil, which in turn winds a weak auxiliary spring via a ratchet and pawl mechanism or imparts direct magnetic force to the escapement linkage. The strength of each impulse is regulated through controlled voltage and current, governed by Ohm's law (), where current determines the magnetic force, minimizing torque variations and maintaining steady oscillation of the balance or pendulum. This process repeats cyclically, with the auxiliary power source ensuring uninterrupted drive during rewinding, thus preserving timing accuracy. Batteries typically last 1-2 years before replacement.[17] Key characteristics of the electric remontoire include its elimination of mechanical wear associated with traditional springs or weights, as the electrical impulses reduce friction in the power transmission path, leading to high precision suitable for automotive and domestic use. Its compact form factor makes it ideal for integration into vehicle instruments, though it necessitates a reliable power source. The system is vulnerable to electrical fluctuations, such as voltage drops from aging batteries, which can affect impulse consistency and overall performance.[17][20] Notable examples trace back to early 20th-century innovations, such as the Swiss Schild Electrora (Calibre 3000, introduced in 1926) and Reform (Calibre 5000, 1945) movements developed for automobile and aviation clocks, featuring quiet electromagnetic operation with Invar Breguet springs for temperature stability. These designs evolved into electro-mechanical hybrids by the 1960s, bridging traditional mechanics with emerging quartz technology for enhanced reliability in automotive timing.[17][21] The primary advantages of the electric remontoire lie in its low maintenance requirements, as it obviates the need for manual winding and reduces wear on mechanical components, while delivering consistent torque for superior accuracy in portable precision timing devices. However, its dependency on electrical power introduces disadvantages, including susceptibility to battery failure or environmental interference, limiting its use in fully unpowered or rugged environments compared to self-sustaining mechanical alternatives.[17]Applications
In Tower and Precision Clocks
In tower clocks, remontoires play a crucial role in isolating the escapement from extensive gear trains spanning significant distances and bearing heavy loads, thereby mitigating torque fluctuations induced by environmental factors such as wind loads on the tower structure or temperature-induced expansions in the drive weights.[12] This isolation ensures a steady power delivery to the timekeeping mechanism, independent of irregularities from the main driving system or auxiliary functions like chiming. Typically, gravity-type remontoires are favored in these large-scale installations due to their reliability with substantial power reserves of 7 to 14 days, allowing weekly winding without compromising precision.[22][18] In precision clocks, particularly astronomical regulators used in observatories, remontoires enhance accuracy by delivering consistent impulses to the pendulum, often achieving rates better than 1 second per month. A notable example is the Shortt-Synchronome free-pendulum clock from the 1920s, which employed a double gravity remontoire system—comprising two impulsing arms to provide periodic lifts to maintain pendulum amplitude—enabling exceptional performance with errors as low as 1 to 2 milliseconds per day in optimal conditions.[23][24] These devices were essential for scientific timekeeping, supporting applications like celestial observations and standard time dissemination. Implementation of remontoires in tower and precision clocks presents specific challenges, including the need for precise synchronization between the going train and striking mechanisms to avoid disruptions during hourly chimes, as well as rigorous maintenance to address dust accumulation, alignment shifts from vibrations, and wear in public or exposed tower environments.[12] These factors demand skilled horological expertise, contributing to higher costs and fragility compared to simpler mechanical setups.[17] Historically, remontoires significantly advanced reliable public timekeeping; for instance, the Great Clock at Westminster, installed in 1859, featured an innovative double three-legged gravity escapement designed by Edmund Beckett Denison, which functions similarly to a remontoire by providing constant-force impulses to the pendulum for consistent operation across its massive frame.[25] This enabled accurate time display to the public via large dials, setting a benchmark for civic clocks. However, mechanical remontoires declined after the 1930s, largely superseded by electric master systems and synchronous motors that offered reduced maintenance and automated winding, though they persist in restorations of heritage tower clocks to preserve original mechanics.[18][17]In Watches and Chronometers
In pocket watches during the 18th and 19th centuries, spring remontoires were primarily employed to deliver consistent power to verge or lever escapements, mitigating the irregular torque from the mainspring's unwinding arc that could otherwise cause rate variations.[26] These mechanisms used a secondary spring and lever to intermittently recharge, ensuring more uniform impulses to the balance wheel despite the mainspring's declining force over time.[11] A notable example appears in Abraham-Louis Breguet's sympathique clocks, where a remontoire in the clock's going train provided constant torque to wind and regulate an associated pocket watch via a lever system, three times every half hour, enhancing the portability and precision of the paired timepiece.[27] In marine chronometers, the remontoire's design drew significant influence from John Harrison's H4 timekeeper, completed in 1759, which incorporated the first spring remontoire in watchmaking to maintain reliable operation amid the challenges of sea voyages.[28] This device operated eight times per minute, rewinding every 7.5 seconds to supply steady impulses to the escapement, thereby resisting the effects of ship tilt and motion through a fused spring arrangement that isolated the balance from broader gear train disturbances.[29] By stabilizing power delivery, the remontoire helped preserve the chronometer's accuracy for determining longitude at sea, a critical advancement during the Age of Sail when positional errors could lead to navigational disasters.[30] Adaptations for portability in these devices required extensive miniaturization, with remontoire components often scaled to under 1 cm to fit within the compact cases of pocket watches and chronometers while preserving mechanical integrity.[31] Integration with tourbillons provided dual compensation, as seen in Breguet's designs where the remontoire d'égalité worked alongside the rotating cage to counter both torque inconsistencies and gravitational effects in varying orientations.[32] These configurations typically supported 24- to 48-hour power reserves, balancing the need for autonomy with the constraints of mobile use.[11] Performance improvements from remontoires in watches and chronometers were substantial, reducing positional rate errors to as low as 1-2 seconds per day across multiple orientations, far surpassing earlier mechanisms prone to 10-20 seconds daily drift.[28] Harrison's H4 exemplified this, losing only five seconds over an 81-day transatlantic trial, enabling precise longitude calculations essential for safe maritime navigation.[29] By the 20th century, remontoires in portable timepieces were largely phased out as advancements in balance spring materials, such as alloys with improved elasticity and temperature resistance, rendered constant-force mechanisms less necessary for achieving high accuracy.[2] Their principles persist in high-end replicas, such as Derek Pratt's reconstruction of Harrison's H4, which faithfully reproduces the original remontoire to demonstrate historical precision techniques.[33]Modern Horological Uses
In the post-quartz era, remontoires have experienced a revival as constant-force complications in luxury wristwatches, particularly integrated with tourbillons to enhance precision by delivering impulses at regular intervals of 1 to 60 seconds. A. Lange & Söhne pioneered this resurgence in the 2000s, incorporating remontoire mechanisms in models like the Lange 31 (introduced 2007), which retensions every 10 seconds for a 31-day power reserve, and the Zeitwerk series, where a 60-second remontoire powers digital jumping numerals while maintaining consistent torque to the escapement. These implementations ensure stable amplitude and rate accuracy throughout the power reserve, often achieving chronometer-level performance with variations under 4 seconds per day.[1][2] Hybrid systems combining remontoires with advanced escapements have become prominent in independent watchmaking during the 2010s and 2020s, aiding COSC certification by minimizing power variations. F.P. Journe's Tourbillon Souverain (launched 1999, produced through 2018) features a patented one-second remontoire d'égalité concentric with the tourbillon, delivering dead-beat seconds and an amplitude of 280 degrees for superior isochronism. In the Chronomètre Optimum (2012), Journe employs a hybrid escapement blending Breguet's natural escapement with the Swiss lever, paired with a titanium remontoire for 50-hour amplitude stability over a 70-hour reserve, emphasizing friction reduction without silicon. Independent makers like Ferdinand Berthoud integrate remontoires with fusée-and-chain systems in the FB 2RE (2020), further stabilizing energy delivery for high-precision chronometry.[34][35][2] Modern adaptations leverage microfabrication techniques, such as the LIGA process, to produce miniaturized spring remontoires and escapement components with high aspect ratios and precision, enabling slimmer profiles in contemporary movements. UV-LIGA, in particular, fabricates intricate parts like levers and wheels for prototyping and small-batch production in Swiss watchmaking. Current trends in 2025 high-end releases continue this emphasis on craftsmanship to counter quartz dominance, as seen in Urban Jürgensen's UJ-1 tourbillon with a one-second remontoir d'égalité—the first series-produced wristwatch using Derek Pratt's design—and Ferdinand Berthoud's Naissance d’une Montre 3, which employs a fusée-and-chain constant-force mechanism as an alternative to traditional remontoires. These innovations highlight remontoires' role in showcasing mechanical artistry and reliability.[36][37][38][2]References
- https://commons.wikimedia.org/wiki/File:Electric_remontoire_car_clock.jpg