An automatic watch.
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. Whereas a quartz watch is powered by electricity, a mechanical watch is powered by a mainspring which must be rewound for the watch to keep time.
The name comes from the point that, instead of the owner having to wind the watch to power, the watch winds itself "automatically" when worn regularly. To accomplish this, the watch contains a fan-shaped rotor (weight) 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 and the staff is attached to a ratcheting winding mechanism inside the watch. Movement of the user's arm is thereby translated into circular motion of the rotor that eventually winds the mainspring. The fully-wound mainspring in a typical watch can store enough energy for roughly two days while motionless. Most automatic watches can also be wound manually by turning the crown (a notable exception is Seiko's wide-ranging line of watches based on the company's 7S26 movement, which cannot be hand-wound).
On some automatic watches the rotor is visible through a transparent case back, called a display back or exhibition back. In these cases the rotors are often engraved or decorated in some way.
For people who do not wear their watch every day, watch winders are available to store automatic watches. A watch winder is a device that can hold one or more watches and moves them in circular patterns to mimic the human motion that 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.
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.
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.[1]
Perrelet sold some of his watches to a contemporary watchmaker, Abraham-Louis Breguet who improved the mechanism in his own version of the design; calling his watches "perpetuelles" (possibly the source for Rolex's brand name of the "Perpetual" watch brand).[2] [3]
The mechanism was more successful on 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[4], who took out a UK patent with his financial backer, Harry Cutts, on 7 July 1923, and the Swiss patent on 16 October 1923.[5] It 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 if the wearer removed it. It did not have a conventional stem winder, so the hands could be 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. 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 for up to 35 hours if the wearer removed the watch.
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. 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 millimetres.
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. Whereas a quartz watch is powered by electricity, a mechanical watch is powered by a mainspring which must be rewound for the watch to keep time.
The name comes from the point that, instead of the owner having to wind the watch to power, the watch winds itself "automatically" when worn regularly. To accomplish this, the watch contains a fan-shaped rotor (weight) 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 and the staff is attached to a ratcheting winding mechanism inside the watch. Movement of the user's arm is thereby translated into circular motion of the rotor that eventually winds the mainspring. The fully-wound mainspring in a typical watch can store enough energy for roughly two days while motionless. Most automatic watches can also be wound manually by turning the crown (a notable exception is Seiko's wide-ranging line of watches based on the company's 7S26 movement, which cannot be hand-wound).
On some automatic watches the rotor is visible through a transparent case back, called a display back or exhibition back. In these cases the rotors are often engraved or decorated in some way.
For people who do not wear their watch every day, watch winders are available to store automatic watches. A watch winder is a device that can hold one or more watches and moves them in circular patterns to mimic the human motion that 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.
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.
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.[1]
Perrelet sold some of his watches to a contemporary watchmaker, Abraham-Louis Breguet who improved the mechanism in his own version of the design; calling his watches "perpetuelles" (possibly the source for Rolex's brand name of the "Perpetual" watch brand).[2] [3]
The mechanism was more successful on 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[4], who took out a UK patent with his financial backer, Harry Cutts, on 7 July 1923, and the Swiss patent on 16 October 1923.[5] It 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 if the wearer removed it. It did not have a conventional stem winder, so the hands could be 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. 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 for up to 35 hours if the wearer removed the watch.
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. 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 millimetres.
