The Rolex Oysterquartz was a quartz watch made by Rolex .
56-457: Unlike most watches, The Rolex Oysterquartz features a mechanical lever escapement driven by a simple permanent magnet moving coil motor mechanically similar to a d'Arsonval galvanometer . At the end of the 1970s, the Swiss watch industry was affected by the quartz crisis . Japanese watchmakers supplied the world market with large quantities of quartz watches . Rolex responded by introducing
112-506: 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
168-406: 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
224-404: 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
280-425: 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
336-456: 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
392-419: 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
448-404: 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
504-633: A new line of watches, producing the Datejust Oysterquartz. It faced the Asian markets seeking to keep alive interest in Swiss watchmaking, an industry that seemed dominated by the Japanese quartz watch. The Datejust Oysterquartz dates back to 1976. The design differs greatly from the classic Rolex line and carved characteristics of the period: a completely angular case, an integrated band with
560-409: A pallet. As shown in the diagram, the escape wheel rotates clockwise and the entrance tooth is locked in place against the entrance pallet, the lever held in place by the left banking pin. The impulse pin is located within the lever fork and the balance wheel is near its center position. To get started, the lever fork must receive a small impulse from the anti-clockwise rotation of the balance wheel via
616-753: A polished finish, and sapphire glass . The whole range consisted of three versions: gold , steel with white gold bezel, and steel and yellow gold. The Datejust Oysterquartz was initially overlooked in Europe but was much sought-after in the Asian and American markets. There was renewed interest in the watch once Rolex decided to take the Oysterquartz out of production. The era of the Rolex quartz watch ended in 2001, after less than 30 years. The Rolex Datejust Oysterquartz began to appear in auction catalogues, becoming
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#1732779717129672-507: 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
728-523: A valued collectors’ object. Model numbers of the Rolex Oysterquartz include: Lever escapement The lever escapement , invented by the English clockmaker Thomas Mudge in 1754 (albeit first used in 1769), is a type of escapement that is used in almost all mechanical watches , as well as small mechanical non-pendulum clocks, alarm clocks , and kitchen timers . An escapement
784-429: 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
840-424: 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
896-576: Is a mechanical linkage that delivers impulses to the timepiece's balance wheel , keeping it oscillating back and forth, and with each swing of the balance wheel allows the timepiece's gear train to advance a fixed amount, thus moving the hands forward at a steady rate. The escapement is what makes the "ticking" sound in mechanical watches and clocks. The lever escapement was invented by British clockmaker Thomas Mudge around 1754, and improved by Abraham-Louis Breguet (1787), Peter Litherland (1791), and Edward Massey (1800). Its modern ("table roller") form
952-403: 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
1008-415: Is fixed to the balance wheel shaft. The balance wheel is returned towards its static center position by an attached balance spring (not shown in the diagram). In modern design it is common for the pallet mountings and the fork to be made as a single component. The lever is mounted on a shaft and is free to rotate between two fixed banking pins. At rest one of the escape wheel teeth will be locked against
1064-415: 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
1120-424: 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
1176-407: 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
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#17327797171291232-454: 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
1288-426: Is very precise. Third, it is self-starting; if the watch is jarred in use and the balance wheel stops, it will start again. A cheaper and less accurate version of the lever escapement, called the pin pallet escapement , invented by Georges Frederic Roskopf in 1867, is used in clocks and timers. The escape wheel is geared to the watch's wheel train , which applies torque to it from the mainspring . The rotation of
1344-420: 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
1400-433: 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
1456-399: The 24-degree angle between two teeth. The impulse received by the entrance pallet as the tooth moves over the impulse face is transferred by the lever to the balance wheel via the ruby impulse pin on the roller of the balance wheel. The lever moves until it rests against the right banking pin; it is held in this position by the force of the exit tooth against the exit pallet jewel (called
1512-412: 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
1568-422: 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
1624-401: The balance wheel an impulse, so there are two impulses per cycle. Despite being locked at rest most of the time, the escape wheel rotates typically at an average of 10 rpm or more. The origin of the "tick tock" sound is caused by this escapement mechanism. As the balance wheel rocks back and forth, the ticking sound is heard. The reliability of the modern lever escapement depends upon draw;
1680-415: 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
1736-485: 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
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1792-399: The draw). This means that in order to unlock the wheel it must be turned backwards by a small amount, which is done by the return momentum of the balance wheel via the impulse pin. After the exit tooth locks, the balance wheel rotates anti-clockwise, free of interference from the escapement until the hairspring pulls it back clockwise, and the impulse pin re-enters the fork. This will unlock
1848-411: 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
1904-415: The escape wheel is controlled by the pallets . The escape wheel has specially shaped teeth of either ratchet or club form, which interact with the two jewels called the entrance and exit pallets. The escape wheel, except in unusual cases, has 15 teeth and is made of steel. These pallets are attached solidly to the lever, which has at its end a fork to receive the ruby impulse pin of the balance roller which
1960-542: The escapement unlocking. Most modern mechanical watches are jeweled lever watches, using synthetic ruby or sapphire jewels for the high-wear areas of the watch. A cheaper, less accurate version of the lever escapement is used in alarm clocks , kitchen timers , mantel clocks and, until the late 1970s, cheap watches, called the Roskopf , pin-lever , or pin-pallet escapement after Georges Frederic Roskopf , who mass produced it from 1867. It functions similarly to
2016-404: The escapement, releasing the escape wheel so that the exit tooth can slide over the impulse plane of the exit pallet, which transfers a clockwise impulse to the balance wheel's impulse pin via the lever fork, while pushing the lever up against the left banking pin. The escape wheel drops again until the entrance tooth locks on the entrance pallet now being held in place by the left banking pin via
2072-413: 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
2128-480: 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
2184-400: The impulse pin (say by being shaken) which rotates the lever slightly clockwise off the left banking pin. This unlocks the entrance pallet allowing the wheel to rotate clockwise. As the powered escape wheel rotates clockwise, the entrance tooth slides across the sloping impulse plane of the entrance pallet. This turns the pallets about their axis, which places the exit pallet into the path of
2240-492: 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
2296-424: The lever, except that the lever pallet jewels are replaced by vertical metal pins. In a lever escapement, the pallets have two angled faces, the locking face and the impulse face, which must be carefully adjusted to the correct angles. In the pin pallet escapement, these two faces are designed into the shape of the escape wheel teeth instead, eliminating complicated adjustments. The pins are located symmetrically on
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2352-425: The lever, making beat adjustment simpler. Watches that used these escapements were called pin lever watches , and have been superseded by cheap quartz watches. One recent trend in escapement design is the use of new materials, many borrowed from the semiconductor fabrication industry. A problem with the lever escapement is friction. The escape wheel tooth slides along the face of the pallet, causing friction, so
2408-405: The lever. The balance wheel continues clockwise, again free from interference until it is pulled back by the hairspring to the center position. The cycle then starts again. Each back and forth movement of the balance wheel from and back to its center position corresponds to a drop of one tooth (called a beat). A typical watch lever escapement beats at 18,000 or more beats per hour. Each beat gives
2464-438: 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,
2520-406: 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
2576-425: 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
2632-567: The pallets and teeth must be lubricated. The oil eventually thickens, causing inaccuracy, and requiring cleaning and reoiling of the movement about every 4 years. A solution is to make the escape wheel and other parts out of harder materials than steel, eliminating the need for lubrication. Materials being tried include silicon , nickel phosphorus, diamond , and diamond-on-silicon. Ulysse Nardin in 2001, Patek Philippe in 2005, and Zenith in 2013 introduced watches with silicon escape wheels. Balance wheel A balance wheel , or balance ,
2688-420: The pallets are angled so that the escape wheel must recoil a small amount during the unlocking. The draw holds the lever against the banking pins during the detached portion of the operating cycle. Draw angle is typically about 11-15 degrees to the radial. Early lever escapements lacked draw (indeed some makers considered it injurious as a cause of extra friction in unlocking); as a result a jolt could result in
2744-439: 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,
2800-419: The rotating escape wheel. Once the entrance tooth leaves the impulse plane of the entrance pallet, the wheel is able to turn a small amount (called the drop) until the exit tooth of the escape wheel lands on the locking face of the exit pallet. The wheel is said to be locked on the exit pallet. From the release from the entrance pallet to this point, the escape wheel will have turned through exactly one half of
2856-482: 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
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#17327797171292912-400: 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
2968-433: 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
3024-477: Was developed by George Savage in the early 1800s. Since about 1900 virtually every mechanical watch, alarm clock and other portable timepiece has used the lever escapement. The advantages of the lever are, first, that it is a "detached" escapement; it allows the balance wheel to swing completely free of the escapement during most of its oscillation, except when giving it a short impulse, improving timekeeping accuracy. Second, due to "locking" and "draw" its action
3080-401: 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
3136-413: 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
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