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Encyclopedia > Automatic watch
The underside view of an automatic watch with a transparent case back. The rotor and the balance wheel are plainly visible
The underside view of an automatic watch with a transparent case back. The rotor and the balance wheel are plainly visible

An automatic watch (also called a self-winding watch or, in Rolex movements, "perpetual") is a mechanical watch, typically with a balance wheel escapement, whose mainspring is wound by the motion of the wearer's arm, instead of having to be wound manually every day. Image File history File linksMetadata Download high-resolution version (629x810, 145 KB) View of an ETA automatic watch movement in a watch with a see through caseback. ... Image File history File linksMetadata Download high-resolution version (629x810, 145 KB) View of an ETA automatic watch movement in a watch with a see through caseback. ... Rolex SA is a Swiss manufacturer of mostly mechanical wristwatches and accessories renowned for their dependability, prestige, and cost (from a few thousand to more than one hundred thousand U.S. dollars). ... It has been suggested that this article or section be merged into Watch. ... Russian Poljot Siberia model finished movement viewed through crystal back For other uses, see Watch (disambiguation). ... Red arrows indicate the balance wheel on this movement. ... A simple escapement. ... Mainspring (U.S.A. motor spring): In a watch, long strip of hardened and blued steel or of a specially alloyed steel, between 2oo & 3oo millimeters in length and 0. ...

Contents

Overview

An automatic watch (also called a self-winding watch or, in Rolex movements, "perpetual") is a mechanical watch, typically with a balance wheel escapement, whose mainspring is wound by the motion of the wearer's arm, instead of having to be wound manually every day - that is, it converts kinetic energy to potential energy. Rolex SA is a Swiss manufacturer of mostly mechanical wristwatches and accessories renowned for their dependability, prestige, and cost (from a few thousand to more than one hundred thousand U.S. dollars). ... It has been suggested that this article or section be merged into Watch. ... Russian Poljot Siberia model finished movement viewed through crystal back For other uses, see Watch (disambiguation). ... Red arrows indicate the balance wheel on this movement. ... A simple escapement. ... Mainspring (U.S.A. motor spring): In a watch, long strip of hardened and blued steel or of a specially alloyed steel, between 2oo & 3oo millimeters in length and 0. ...


Derivation of the name- "automatic"

The name comes from the fact that, instead of the wearer having to wind the watch to power its motive spring, the watch winds itself "automatically" when worn regularly.


How it works

To accomplish this, the watch contains a fan-shaped rotor (a/k/a a weight or an oscillating mass) within the watch case. The normal movements of the user's arm and wrist cause the rotor to pivot back-and-forth on its staff which is attached to a ratcheted winding mechanism. The motion of the wearer's arm is thereby translated into the circular motion of the rotor that through a series of reverser and reducing gears, eventually winds the mainspring. The fully-wound mainspring in a typical watch can store enough energy reserve for roughly two days, however some models made specifically to have longer power reserves can last longer. Many automatic watches can also be wound manually by turning the crown (a notable exception is Seiko's wide-range of watches based on the company's 7S26 movement, which cannot be hand-wound).


Why it doesn't over-wind itself

On June 16, 1863, Adrien Philippe (of Patek Philippe) is credited with Patent No.58941, for the "slipping mainspring". This particular invention allowed the simultaneous winding of two or more mainspring barrels, certainly a different invention with a different purpose. However, the technology of his invention is said to be the foundation for the development of self-winding wristwatches. is the 167th day of the year (168th in leap years) in the Gregorian calendar. ... Year 1863 (MDCCCLXIII) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... Adrien Philippe, c. ... Patek Philippe & Co. ...


The Slipping Spring

This "slipping" spring allows the mainspring to slide or slip a few degrees relative to the inside of the barrel while still staying fully wound. The end of the slipping spring moves from one groove to another on the inside the barrel, stopping each time, and thus keeping the spring under constant tension.


This attachment of spring steel is sometimes referred to as a “bridle”. This bridle slips along the barrel wall before excess pressure is passed to the going train and causing a defect known as “banking.” Banking occurs when the balance amplitude is too high and the impulse jewel strikes the back of the horns of the pallet fork. The “bridle” must also grip the barrel wall sufficiently to not slip down either too rapidly, or too slowly, a defect known as “mainspring creep” which results in a shortened reserve power time. http://www.bhi.co.uk/hints/automsp.htm The slipping bridle on the outer end of the mainspring is illustrated here. (1). the bridle (in the barrel), (2) maintains outward pressure on the outermost coil of the mainspring (3). At less than full wind, the bridle pressure causes the outer tip of the spring to catch in a notch in the barrel wall (4) and maintain its position. As the mainspring reaches full wind, the outer end of the spring jumps out of the notch and releases tension by slipping across the smooth section of the barrel wall (5) until it catches in the next notch. See the photo illustration at TimeZone click here. [1]


The Display Case back

On some automatic watches the rotor and its action are visible through a transparent case back, called a display back or exhibition back. In these watches, the rotors are often engraved or decorated in some way. Rolex is one of the few automatic watch manufacturers that traditionally eschews the transparent case back, mainly for enhanced water resistance.


The Watch Winder

For people who do not wear their automatic watch every day, watch winders are available to store automatic watches and keep them wound. This is particularly advantageous if the watch had complex or perpetual calendars or moon phases. A watch winder is a device that can hold one or more watches and moves them in circular patterns to approximate the human motion that otherwise keeps the self-winding mechanism working. A mechanical watch should be kept wound and running as much as possible to prevent its lubricants from congealing over time, which diminishes accuracy. A full service (which involves disassembly, cleaning and re-lubrication) should be performed at least every five years to keep the movement as accurate as possible.


The Auto-Quartz or Kinetic Movement

A more recent evolution of the automatic watch uses a self-winding mechanism to charge a battery or capacitor which in turn powers a quartz movement. This automatic quartz arrangement provides the accuracy of quartz without the need to replace the battery or capacitor until it reaches the end of its life, which may be decades. Symbols representing a single Cell (top) and Battery (bottom), used in circuit diagrams. ... Capacitors: SMD ceramic at top left; SMD tantalum at bottom left; through-hole tantalum at top right; through-hole electrolytic at bottom right. ... A crystal oscillator is an electronic circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. ... Automatic quartz is a collective term describing watch movements that combine a self-winding rotor mechanism (as used in automatic mechanical watches) to generate electricity with a piezoelectric quartz crystal as its timing element. ...


History

  • Perrelet

The Swiss watchmaker Abraham-Louis Perrelet invented a self-winding mechanism in 1770 for fob watches. It worked on the same principle as a modern pedometer, and was designed to wind as the owner walked, using an oscillating weight inside the large watch that moved up and down. The Geneva Society of Arts reported in 1776 that fifteen minutes walking was necessary to wind the watch sufficiently for eight days, and the following year reported that it was selling well.[2] A gold pocket watch with hunter case and watch chain A pocket watch (or pocketwatch) usually is a strapless personal timepiece that is carried in a pocket. ... This article does not cite any references or sources. ...

  • Breguet

Perrelet sold some of his watches to a contemporary watch making luminary, Abraham-Louis Breguet who improved upon the mechanism in his own version of the design, calling his watches "perpetuelles" the French word for perpetual and possibly the source for Rolex's name for its automatic movements, the "Perpetual").[3] [4] Abraham-Louis Breguet or Bréguet (10 January 1747 – 17 September 1823), born in Neuchâtel in Switzerland, made many innovations in the course of a career in watchmaking in France. ...

  • Harwood

The mechanism was more successful in wristwatches because the rotor could operate every time that the owner moved his or her arm. However the first version did not appear until the 20th century. It was invented by a watch repairer from the Isle of Man named John Harwood in 1923[5], who took out a UK patent with his financial backer, Harry Cutts, on 7 July 1923, and a corresponding Swiss patent on 16 October 1923.[6] The Harwood system used a pivoting weight which swung as the wearer moved, and which in turn wound the mainspring. When fully wound, the 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 went on sale in 1928 and 30,000 were made until the company collapsed in 1931 as a result of the Great Depression. (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901–2000 in the sense of the Gregorian calendar (1900–1999... is the 188th day of the year (189th in leap years) in the Gregorian calendar. ... Year 1923 (MCMXXIII) was a common year starting on Monday (link will display the full calendar) of the Gregorian calendar. ... is the 289th day of the year (290th in leap years) in the Gregorian calendar. ... Year 1923 (MCMXXIII) was a common year starting on Monday (link will display the full calendar) of the Gregorian calendar. ... The Great Depression was a dramatic, worldwide economic downturn beginning in some countries as early as 1928. ...

  • Rolex

The Rolex Watch Company had taken up the design in 1930 and used it as the basis for the Rolex Oyster Perpetual, in which the centrally mounted semi-circular weight could rotate through a full 360 degrees rather than the 300 degrees of the original design. Rolex's version also increased the amount of energy stored in the mainspring, allowing it to run autonomously for up to 35 hours.

  • Omega

Most mechanical watches sold today are automatic. A notable exception is the Omega Speedmaster Professional "Moonwatch", the model used by NASA astronauts during the Apollo Program. Reportedly NASA assumed that the automatic winding mechanism was based on pendulum action like Harwood's original design, requiring either a gravity field or constant acceleration. The weightless environment therefore raised doubts about the ability of an automatic watch to wind itself. In fact a full 360-degree winding mechanism should work even better in low or zero gravity, where the friction experienced by the mechanism is lower. The rotor can thus move longer and transfer more energy into the spring. The rotor is in any case easily activated by momentum and not dependent on gravity. Omega SA is a watch company based in Biel/Bienne Switzerland and is one of the more prestigious brands in timepieces. ... The Omega Speedmaster, the legendary Moonwatch, selected by NASA for all the Apollo missions Launched in 1957 by Omega, the Moonwatch is a type of Omega Speedmaster watch which was selected by the NASA for the Project Apollo. ... The National Aeronautics and Space Administration (NASA) is an agency of the United States government, responsible for the nations public space program. ... Project Apollo was a series of human spaceflight missions undertaken by the United States of America (NASA) using the Apollo spacecraft and Saturn launch vehicle, conducted during the years 1961 – 1975. ...

  • Patek Philippe

Because of the fact that a manually wound wristwatch does not require the weighted rotor which is necessary for an automatic watch, some extremely fine watch companies, such as Patek Philippe, continue to design manually wound watches, which can achieve a case thickness as low as 1.77 millimeters. Patek Philippe & Co. ...


References

  1. ^ "What exactly is...a slipping spring," hr: Watches March/April 2005 at page 90.
  2. ^ Biography of Abraham Louis Perrelet
  3. ^ Who invented the automatic watch?
  4. ^ Timekeeping in Europe and China : Watches & Wonders timeline at Worldtempus.com
  5. ^ Press release by UK Patent Office on 80th anniversary of self-winding watch patent
  6. ^ Brainy History - 16 October 1923

Hampel, H., Automatic Wristwatches from Switzerland, Schiffer, Atglen, 1994.


Links

  • A detailed evaluation of the mechanics of the Seiko 7S26 automatic watch movement


 
 

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