Misplaced Pages

#533466

66-460: The Futurematic is a self-winding wrist watch without a crown. It was manufactured between 1951 and 1959 by the Swiss watch manufacturer Jaeger-LeCoultre . The Futurematic was the world's first watch without a crown for winding the mainspring , having a flat crown on the back that was used solely for setting the time. The Futurematic was produced with two different watch dials . Both dials have

132-409: A mechanical watch the watch's gears are turned by a spiral spring called a mainspring . In a manual watch , energy is stored in the mainspring by turning a knob, the crown , on the side of the watch. Then the energy from the mainspring powers the watch movement until it runs down, requiring the spring to be wound again. A self-winding watch movement has a mechanism which winds the mainspring using

198-423: A rotating unbalance mass segment made of tungsten encircles the entire mechanism, rotating on carbon rollers whenever the watch moves. A system of clutch wheels captures power. No rotor means thinner watches and an ultradense weight swinging around a greater radius means a better chance of achieving a greater power reserve with same amount of arm movement. Balance wheel A balance wheel , or balance ,

264-506: A balance wheel in 1753, using a bimetallic "compensation curb" on the spring, in the first successful marine chronometers, H4 and H5. These achieved an accuracy of a fraction of a second per day, but the compensation curb was not further used because of its complexity. A simpler solution was devised around 1765 by Pierre Le Roy , and improved by John Arnold , and Thomas Earnshaw : the Earnshaw or compensating balance wheel. The key

330-457: A central time indicator for hours and minutes. The earlier dial has a small second indication and a power reserve indicator and was used in model E501 . The later dial version called Futurematic Porthole had two portholes and was used in model E502 . Below these portholes are rotating discs, one as a power reserve indicator with a colour change of red or blue (two variants, with the color indicating high reserve ) to white (for low reserve ),

396-406: A clock or watch without balance spring, the drive force provides both the force that accelerates the wheel and also the force that slows it down and reverses it. If the drive force is increased, both acceleration and deceleration are increased, this results in the wheel getting pushed back and forth faster. This made the timekeeping strongly dependent on the force applied by the escapement. In a watch

462-417: A different solution. In 1948, Eterna introduced the solution that is still in use today: ball bearings . Ball bearings provide robust support for a heavy object to rotate smoothly and reliably even under abnormal stress, such as if the watch were dropped. Eterna adopted geared bidirectional winding shortly afterwards. By the 1960s, automatic winding had become widespread in quality mechanical watches. Because

528-404: A few cases stackfreeds ) to equalize the force from the mainspring reaching the escapement, to achieve even minimal accuracy. Even with these devices, watches prior to the balance spring were very inaccurate. The idea of the balance spring was inspired by observations that springy hog bristle curbs, added to limit the rotation of the wheel, increased its accuracy. Robert Hooke first applied

594-425: A low thermal coefficient of elasticity alloy such as Nivarox . The two alloys are matched so their residual temperature responses cancel out, resulting in even lower temperature error. The wheels are smooth, to reduce air friction, and the pivots are supported on precision jewel bearings . Older balance wheels used weight screws around the rim to adjust the poise (balance), but modern wheels are computer-poised at

660-456: A metal spring to the balance in 1658 and Jean de Hautefeuille and Christiaan Huygens improved it to its present spiral form in 1674. The addition of the spring made the balance wheel a harmonic oscillator , the basis of every modern clock . This means the wheel vibrated at a natural resonant frequency or "beat" and resisted changes in its vibration rate caused by friction or changing drive force. This crucial innovation greatly increased

726-419: A much larger effect in a balance spring made of plain steel is that the elasticity of the spring's metal decreases significantly as the temperature increases, the net effect being that a plain steel spring becomes weaker with increasing temperature. An increase in temperature also increases diameter of a steel or brass balance wheel, increasing its rotational inertia, its moment of inertia , making it harder for

SECTION 10

#1732783984534

792-404: A negative quadratic temperature coefficient. This alloy, named anibal, is a slight variation of invar. It almost completely negated the temperature effect of the steel hairspring, but still required a bimetal compensated balance wheel, known as a Guillaume balance wheel. This design was mostly fitted in high precision chronometers destined for competition in observatories. The quadratic coefficient

858-507: A rate of 4 beats per second (14,400 BPH). Watches made prior to the 1970s usually had a rate of 5 beats per second (18,000 BPH). Current watches have rates of 6 (21,600 BPH), 8 (28,800 BPH) and a few have 10 beats per second (36,000 BPH). Audemars Piguet currently produces a watch with a very high balance vibration rate of 12 beats/s (43,200 BPH). During World War II , Elgin produced a very precise stopwatch for US Air Force bomber crews that ran at 40 beats per second (144,000 BPH), earning it

924-409: A regulator for the balance spring with micrometre scaling and a unique wire hook mechanism to prevent overwinding of the mainspring. A complete unwinding of the mainspring was mechanically inhibited to allow the watch to start running shortly after putting it on the wrist. The last calibres of both models have Parachoc shock protection and therefore contain a "P" in the name, P827 and KP837, whereas

990-412: A series of reverser and reducing gears, eventually winds the mainspring. There are many different designs for modern self-winding mechanisms. Some designs allow winding of the watch to take place while the weight swings in only one direction while other, more advanced, mechanisms have two ratchets and wind the mainspring during both clockwise and anti-clockwise weight motions. The fully wound mainspring in

1056-508: A subsidiary of Longines-Wittnauer. Therefore, there are differences in the case forms and the dials between the U.S. and the European models. While the European models had only two watch case forms and were produced in three metal variants ( stainless steel , yellow gold , and red gold ), there are more models of the U.S. Futurematics, and an additional case metal variant, 10 carat gold-filled stainless steel cases. Self-winding In

1122-470: A successful design is the watch made by the Swiss watchmaker Abraham-Louis Perrelet , who lived in Le Locle . In late 1776 or early 1777, he invented a self-winding mechanism for pocket watches but the original reports make no mention of the mechanism used, although later evidence could point to a side weight type. The Geneva Society of Arts, reporting on this watch in 1777, stated that 15 minutes walking

1188-419: A typical watch can store enough energy reserve for roughly two days, allowing the watch to keep running through the night while stationary. In many cases automatic wristwatches can also be wound manually by turning the crown, so the watch can be kept running when not worn, and in case the wearer's wrist motions are not sufficient to keep it wound automatically. Self-winding mechanisms continue working even after

1254-429: A watch that is not compensated for the effects of temperature, the weaker spring takes longer to return the balance wheel back toward the center, so the "beat" gets slower and the watch loses time. Ferdinand Berthoud found in 1773 that an ordinary brass balance and steel hairspring, subjected to a 60 °F (33 °C) temperature increase, loses 393 seconds ( 6 + 1 ⁄ 2 minutes) per day, of which 312 seconds

1320-424: A wide temperature range. By the 1870s compensated balances began to be used in watches. The standard Earnshaw compensation balance dramatically reduced error due to temperature variations, but it didn't eliminate it. As first described by J. G. Ulrich, a compensated balance adjusted to keep correct time at a given low and high temperature will be a few seconds per day fast at intermediate temperatures. The reason

1386-437: Is at the end of 1773 when a newspaper reported that Joseph Tlustos had invented a watch that did not need to be wound. But his idea was probably based on the myth of perpetual motion, and it is unlikely that it was a practical solution to the problem of self-winding watches. In 1776 Joseph Gallmayr also stated that he had made a self-winding watch, but there is no evidence to support this claim. The earliest credible evidence for

SECTION 20

#1732783984534

1452-403: Is due to spring elasticity decrease. The need for an accurate clock for celestial navigation during sea voyages drove many advances in balance technology in 18th century Britain and France. Even a 1-second per day error in a marine chronometer could result in a 17-mile (27 km) error in ship's position after a 2-month voyage. John Harrison was first to apply temperature compensation to

1518-498: Is sufficient and all of Breguet's watches used unidirectional winding. Before the invention of the slipping mainspring, automatic watches had a system for locking the weight. Most common, as in the 1780 drawing, when the mainspring was fully wound a lever K was raised that entered a hole N in the weight to prevent it from moving until the mainspring had unwound enough to lower the lever. Different methods were used in side-weight, rotor and center-weight mechanisms. The advent of

1584-415: Is that the moment of inertia of the balance varies as the square of the radius of the compensation arms, and thus of the temperature. But the elasticity of the spring varies linearly with temperature. To mitigate this problem, chronometer makers adopted various 'auxiliary compensation' schemes, which reduced error below 1 second per day. Such schemes consisted for example of small bimetallic arms attached to

1650-424: Is the timekeeping device used in mechanical watches and small clocks , analogous to the pendulum in a pendulum clock . It is a weighted wheel that rotates back and forth, being returned toward its center position by a spiral torsion spring , known as the balance spring or hairspring . It is driven by the escapement , which transforms the rotating motion of the watch gear train into impulses delivered to

1716-407: Is traditionally measured in beats (ticks) per hour, or BPH, although beats per second and Hz are also used. The length of a beat is one swing of the balance wheel, between reversals of direction, so there are two beats in a complete cycle. Balances in precision watches are designed with faster beats, because they are less affected by motions of the wrist. Alarm clocks and kitchen timers often have

1782-454: Is unchanged over a wide temperature range, for balance springs. A solid Invar balance with a spring of Elinvar was largely unaffected by temperature, so it replaced the difficult-to-adjust bimetallic balance. This led to a series of improved low temperature coefficient alloys for balances and springs. Before developing Elinvar, Guillaume also invented an alloy to compensate for middle temperature error in bimetallic balances by endowing it with

1848-540: The Great Depression . 'Bumper' watches were the first commercially successful automatic watches; they were made by several high grade watch manufacturers during the 1930s and 1940s. The Rolex Watch Company improved Harwood's design in 1930 and used it as the basis for the Shants Company, in which the centrally mounted semi-circular weight could rotate through a full 360° rather than the about 200° of

1914-420: The elasticity of the spring keep the time between each oscillation or "tick" very constant, accounting for its nearly universal use as the timekeeper in mechanical watches to the present. From its invention in the 14th century until tuning fork and quartz movements became available in the 1960s, virtually every portable timekeeping device used some form of balance wheel. Until the 1980s balance wheels were

1980-433: The foliot , an early inertial timekeeper consisting of a straight bar pivoted in the center with weights on the ends, which oscillates back and forth. The foliot weights could be slid in or out on the bar, to adjust the rate of the clock. The first clocks in northern Europe used foliots, while those in southern Europe used balance wheels. As clocks were made smaller, first as bracket clocks and lantern clocks and then as

2046-412: The pallet fork horns. This will make the watch run fast, and could break the impulse pin. To prevent this, a slipping clutch device is used on the mainspring so it cannot be overwound. The slipping mainspring device was patented by Adrien Philippe , one of the founders of Patek Philippe , on 16 June 1863, long before self-winding wristwatches. In an ordinary watch mainspring barrel , the outer end of

Futurematic - Misplaced Pages Continue

2112-526: The 'bumper' winder. Rolex's version also increased the amount of energy stored in the mainspring, allowing it to run autonomously for up to 35 hours. Information about 18th-century rotor watches was not published until 1949. Although the Oyster Perpetual was probably an original invention, the company may have known of Coviot's 1893 patent that re-invented the 18th-century design. With John Harwood's patent for self-winding watches set to expire in

2178-412: The accuracy of watches, from several hours per day to perhaps 10 minutes per day, changing them from expensive novelties into useful timekeepers. After the balance spring was added, a major remaining source of inaccuracy was the effect of temperature changes. Early watches had balance springs made of plain steel and balances of brass or steel, and the influence of temperature on these noticeably affected

2244-422: The balance spring to accelerate. The two effects of increasing temperature on physical dimensions of the spring and the balance, the strengthening of the balance spring and the increase in rotational inertia of the balance, have opposing effects and to an extent cancel each other. The major effect of temperature which affects the rate of a watch is the weakening of the balance spring with increasing temperature. In

2310-415: The balance wheel. Each swing of the wheel (called a "tick" or "beat") allows the gear train to advance a set amount, moving the hands forward. The balance wheel and hairspring together form a harmonic oscillator , which due to resonance oscillates preferentially at a certain rate, its resonant frequency or "beat", and resists oscillating at other rates. The combination of the mass of the balance wheel and

2376-527: The banking pins as it pivoted". When fully wound, Harwood's watch would run for 12 hours autonomously. It did not have a conventional stem winder, so the hands were moved manually by rotating a bezel around the face of the watch. The watches were first produced with the help of Swiss watch manufacturer Fortis and went on sale in 1928. Thirty thousand were made before the Harwood Self-Winding Watch Company collapsed in 1931 in

2442-401: The bridle will begin to slip before the mainspring is fully wound, a defect known as mainspring creep which results in a shortened reserve power time. A further advantage of this device is that the mainspring cannot be broken by excessive manual winding. This feature is often described in watch company advertising as an unbreakable mainspring . The earliest reference to self-winding watches

2508-485: The center of the wheel, and the shift of mass inward reduces the moment of inertia of the balance, similar to the way a spinning ice skater can reduce their moment of inertia by pulling in their arms. This reduction in the moment of inertia compensated for the reduced torque produced by the weaker balance spring. The amount of compensation is adjusted by moveable weights on the arms. Marine chronometers with this type of balance had errors of only 3–4 seconds per day over

2574-432: The design, and made many self-winding watches from then to about 1810. Although a few self-winding watches and patents for them were made from 1780 on, for more than one hundred years these watches were rare, until the advent of the wrist watch. During the years 1776 to 1810 four different types of weight were used: As noted above, some watches used bidirectional winding and others used unidirectional winding. The latter

2640-411: The drive force provided by the mainspring , applied to the escapement through the timepiece's gear train, declined during the watch's running period as the mainspring unwound. Without some means of equalizing the drive force, the watch slowed down during the running period between windings as the spring lost force, causing it to lose time. This is why all pre-balance spring watches required fusees (or in

2706-408: The early 1930s, Glycine founder Eugène Meylan started developing his own self-winding mechanism. Meylan’s design was unusual: a separate module that could be used with almost any 8.75 ligne (19.74 millimeter) watch movement. In October 1930, Glycine released their first automatic watches using this module, which became the world's first widely-produced automatic watches. This allowed Glycine to survive

Futurematic - Misplaced Pages Continue

2772-604: The end of 1778 he sent a watch to the French Academy of Sciences and a report was written which, together with a drawing, gave a detailed description of the mechanism. Sarton's design is similar to those used in modern wrist watches, although there is no evidence linking the 18th-century design to 20th-century developments. About the beginning of 1779, Abraham-Louis Breguet became aware of Perrelet's watches, probably through Louis Recordon, who travelled from Geneva to London via Le Locle and Paris. Breguet studied and improved

2838-413: The factory, using a laser to burn a precise pit in the rim to make them balanced. Balance wheels rotate about 1 + 1 ⁄ 2 turns with each swing, that is, about 270° to each side of their center equilibrium position. The rate of the balance wheel is adjusted with the regulator , a lever with a narrow slit on the end through which the balance spring passes. This holds the part of the spring behind

2904-585: The first calibres possess KIF shock protection. The comparably elaborate construction of the Futurematic was the base of the advertisement slogan at the time - "the most accurate self-winding watch in the world". Due to the Smoot–Hawley Tariff Act the Futurematics for the U.S. market have a LeCoultre logo instead of Jaeger-LeCoultre printed on the dial and engraved on the calibre and

2970-480: The first large watches after 1500, balance wheels began to be used in place of foliots. Since more of its weight is located on the rim away from the axis, a balance wheel could have a larger moment of inertia than a foliot of the same size, and keep better time. The wheel shape also had less air resistance, and its geometry partly compensated for thermal expansion error due to temperature changes. These early balance wheels were crude timekeepers because they lacked

3036-407: The global depression in the 1930s that caused many Swiss watchmakers to close shop. The next development for automatic watches came in 1948 from Eterna Watch . To wind a watch effectively, one of the chief requirements of a rotor is heft. Until this point, the best bearing used in any watch was a jewel bearing , which perfectly suits the small gears of a watch. A rotor, on the other hand, requires

3102-492: The inside of the balance wheel. Such compensators could only bend in one direction toward the center of the balance wheel, but bending outward would be blocked by the wheel itself. The blocked movement causes a non-linear temperature response that could slightly better compensate the elasticity changes in the spring. Most of the chronometers that came in first in the annual Greenwich Observatory trials between 1850 and 1914 were auxiliary compensation designs. Auxiliary compensation

3168-401: The inside of the case back. As an exception to this rule, all case backs of U.S. and European Futurematic models are internally engraved with LeCoultre , whereas the other markings differ. The cases of the U.S. models and the dials which were produced in the U.S., encase a Swiss-made watch calibre engraved LeCoultre . The U.S. models were distributed by the company Vacheron-Constantin-LeCoultre,

3234-402: The mainspring is fully wound up. If a simple mainspring was used, this would put excessive tension on the mainspring. This could break the mainspring, and even if it did not, it can cause a problem called "knocking" or "banking". The excessive drive force applied to the watch movement gear train can make the balance wheel rotate with excessive amplitude, causing the impulse pin to hit the back of

3300-405: The mainspring to be wound. When the mainspring reaches full wind, its force is stronger than the bridle spring, and further winding pulls the bridle loose from the notches and it simply slides along the wall, preventing the mainspring from being wound further. The bridle must grip the barrel wall with just the right force to allow the mainspring to wind fully but not overwind. If it grips too loosely,

3366-416: The natural motions of the wearer's body. The watch contains an oscillating weight that turns on a pivot. The normal movements of the watch in the user's pocket (for a pocketwatch ) or on the user's arm (for a wristwatch ) cause the rotor to pivot on its staff, which is attached to a ratcheted winding mechanism. The motion of the watch is thereby translated into circular motion of the weight which, through

SECTION 50

#1732783984534

3432-438: The nickname 'Jitterbug'. The precision of the best balance wheel watches on the wrist is around a few seconds per day. The most accurate balance wheel timepieces made were marine chronometers , which were used on ships for celestial navigation , as a precise time source to determine longitude . By World War II they had achieved accuracies of 0.1 second per day. A balance wheel's period of oscillation T in seconds,

3498-406: The other essential element: the balance spring . Early balance wheels were pushed in one direction by the escapement until the verge flag that was in contact with a tooth on the escape wheel slipped past the tip of the tooth ("escaped") and the action of the escapement reversed, pushing the wheel back the other way. In such an "inertial" wheel, the acceleration is proportional to the drive force. In

3564-651: The other porthole had a disc with an arrow to indicate the seconds. The watch calibres K497, K497/1, or KP827 were used for the model E501, whereas the E502 contained K817, K817/1, or KP837. All calibres contain a seconds hacking mechanism, which stops the watch when the crown is slid towards the centre, as well as a centrally suspended rotor for winding the mainspring and thus increasing the power reserve. The rotor swings bidirectionally through an angle of about 190°. All Futurematic calibres contain an antimagnetic and an enlarged and heavier (by about 20%) balance wheel , as well as

3630-425: The outside. Strips of this bimetallic construction bend toward the steel side when they are warmed, because the thermal expansion of brass is greater than steel. The rim was cut open at two points next to the spokes of the wheel, so it resembled an S-shape (see figure) with two circular bimetallic "arms". These wheels are sometimes referred to as "Z-balances". A temperature increase makes the arms bend inward toward

3696-439: The rate. An increase in temperature increases the dimensions of the balance spring and the balance due to thermal expansion . The strength of a spring, the restoring force it produces in response to a deflection, is proportional to its breadth and the cube of its thickness, and inversely proportional to its length. An increase in temperature would actually make a spring stronger if it affected only its physical dimensions. However,

3762-402: The rotor weight needed in an automatic watch takes up a lot of space in the case, increasing its thickness, some manufacturers of quality watches, such as Patek Philippe , continue to design manually wound watches, which can be as thin as 1.77 millimeters. However, in 2007 Carl F. Bucherer implemented a new approach without a rotor, a peripherally mounted power source, where a geared ring and

3828-482: The slit stationary. Moving the lever slides the slit up and down the balance spring, changing its effective length, and thus the resonant vibration rate of the balance. Since the regulator interferes with the spring's action, chronometers and some precision watches have "free sprung" balances with no regulator, such as the Gyromax . Their rate is adjusted by weight screws on the balance rim. A balance's vibration rate

3894-403: The spiral mainspring is attached to the inside of the barrel. In the slipping barrel, the mainspring is attached to a circular steel expansion spring, often called the bridle , which presses against the inside wall of the barrel, which has serrations or notches to hold it. As long as the mainspring is less than fully wound, the bridle holds the mainspring by friction to the barrel wall, allowing

3960-400: The time required for one complete cycle (two beats), is determined by the wheel's moment of inertia I in kilogram-meter and the stiffness ( spring constant ) of its balance spring κ in newton-meters per radian: The balance wheel appeared with the first mechanical clocks, in 14th century Europe, but it seems unknown exactly when or where it was first used. It is an improved version of

4026-433: The timekeeping technology used in chronometers , bank vault time locks , time fuzes for munitions , alarm clocks , kitchen timers and stopwatches , but quartz technology has taken over these applications, and the main remaining use is in quality mechanical watches . Modern (2007) watch balance wheels are usually made of Glucydur , a low thermal expansion alloy of beryllium , copper and iron , with springs of

SECTION 60

#1732783984534

4092-471: The wearer moved, winding the mainspring. The ratchet mechanism wound the mainspring only when moving in one direction. The weight did not rotate a full 360°; spring bumpers limited its swing to about 180°, to encourage a back and forth motion. This early type of self-winding mechanism is now referred to as a 'hammer' or 'bumper'. Like its 18th-century counterparts, Harwood's watch also had a problem with jerking because "the brass weight hit too sharply against

4158-400: The wrist watch after World War I led to renewed interest in self-winding mechanisms, and all four types listed above were used: Invented by John Harwood , a watch repairer from Bolton, England, who took out a UK patent with his financial backer, Harry Cutts, on 7 July 1923, and obtained a corresponding Swiss patent on 16 October 1923. The Harwood system used a pivoting weight which swung as

4224-405: Was necessary to fully wind the watch. In 1777 Abraham-Louis Breguet also became interested in the idea, and his first attempts led him to make a self-winding mechanism with a barrel remontoire . Although a successful design, it was too complex and expensive for it to be manufactured and sold. About the end of 1777 or early 1778, Hubert Sarton designed a watch with a rotor mechanism. Towards

4290-401: Was never used in watches because of its complexity. The bimetallic compensated balance wheel was made obsolete in the early 20th century by advances in metallurgy. Charles Édouard Guillaume won a Nobel prize for the 1896 invention of Invar , a nickel steel alloy with very low thermal expansion, and Elinvar (from élasticité invariable , 'invariable elasticity') an alloy whose elasticity

4356-413: Was to make the balance wheel change size with temperature. If the balance could be made to shrink in diameter as it got warmer, the smaller moment of inertia would compensate for the weakening of the balance spring, keeping the period of oscillation the same. To accomplish this, the outer rim of the balance was made of a "sandwich" of two metals; a layer of steel on the inside fused to a layer of brass on

#533466