A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units: the day, the lunar month, year and galactic year. Devices operating on several physical processes have been used over the millennia.
A pendulum clock is a clock that uses a pendulum, a swinging weight, as its timekeeping element. The advantage of a pendulum for timekeeping is that it is a harmonic oscillator: It swings back and forth in a precise time interval dependent on its length, and resists swinging at other rates. From its invention in 1656 by Christiaan Huygens, inspired by Galileo Galilei, until the 1930s, the pendulum clock was the world's most precise timekeeper, accounting for its widespread use. Throughout the 18th and 19th centuries, pendulum clocks in homes, factories, offices, and railroad stations served as primary time standards for scheduling daily life, work shifts, and public transportation. Their greater accuracy allowed for the faster pace of life which was necessary for the Industrial Revolution. The home pendulum clock was replaced by less-expensive, synchronous, electric clocks in the 1930s and '40s. Pendulum clocks are now kept mostly for their decorative and antique value.
A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet, including metal bands, leather straps or any other kind of bracelet. A pocket watch is designed for a person to carry in a pocket, often attached to a chain.
A cuckoo clock is, typically, a pendulum clock that strikes the hours with a sound like a common cuckoo call and has an automated cuckoo bird that moves with each note. Some move their wings and open and close their beaks while leaning forwards, whereas others have only the bird's body leaning forward. The mechanism to produce the cuckoo call has been in use since the middle of the 1700s and has remained almost without variation.
An escapement is a mechanical linkage in mechanical watches and clocks that gives impulses to the timekeeping element and periodically releases the gear train to move forward, advancing the clock's hands. The impulse action transfers energy to the clock's timekeeping element to replace the energy lost to friction during its cycle and keep the timekeeper oscillating. The escapement is driven by force from a coiled spring or a suspended weight, transmitted through the timepiece's gear train. Each swing of the pendulum or balance wheel releases a tooth of the escapement's escape wheel, allowing the clock's gear train to advance or "escape" by a fixed amount. This regular periodic advancement moves the clock's hands forward at a steady rate. At the same time, the tooth gives the timekeeping element a push, before another tooth catches on the escapement's pallet, returning the escapement to its "locked" state. The sudden stopping of the escapement's tooth is what generates the characteristic "ticking" sound heard in operating mechanical clocks and watches. The first mechanical escapement, the verge escapement, was invented in medieval Europe during the 13th century, and was the crucial innovation which led to the development of the mechanical clock. The design of the escapement has a large effect on a timepiece's accuracy, and improvements in escapement design drove improvements in time measurement during the era of mechanical timekeeping from the 13th through the 19th century.
A pocket watch is a watch that is made to be carried in a pocket, as opposed to a wristwatch, which is strapped to the wrist.
Seiko Holdings Corporation, commonly known as Seiko, is a Japanese maker of watches, clocks, electronic devices, semiconductors, jewelries, and optical products. Founded in 1881, it is known for introducing one of the world's first quartz wrist watches as well as the world's first quartz watch with a chronograph complication.
In horology, a movement, also known as a caliber, is the mechanism of a watch or timepiece, as opposed to the case, which encloses and protects the movement, and the face, which displays the time. The term originated with mechanical timepieces, whose clockwork movements are made of many moving parts. The movement of a digital watch is more commonly known as a module.
The vergeescapement is the earliest known type of mechanical escapement, the mechanism in a mechanical clock that controls its rate by allowing the gear train to advance at regular intervals or 'ticks'. Its origin is unknown. Verge escapements were used from the late 13th century until the mid 19th century in clocks and pocketwatches. The name verge comes from the Latin virga, meaning stick or rod.
Mantel clocks—or shelf clocks—are relatively small house clocks traditionally placed on the shelf, or mantel, above the fireplace. The form, first developed in France in the 1750s, can be distinguished from earlier chamber clocks of similar size due to a lack of carrying handles.
In horology, a tourbillon is an addition to the mechanics of a watch escapement to increase accuracy. It was developed around 1795 and patented by the Swiss-French watchmaker Abraham-Louis Breguet on June 26, 1801. In a tourbillon the escapement and balance wheel are mounted in a rotating cage, with the goal of eliminating errors of poise in the balance giving a uniform weight.
The lever escapement, invented by British clockmaker Thomas Mudge in 1754, 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.
A Roskopf, pin-lever, or pin-pallet escapement is an inexpensive, less accurate version of the lever escapement, used in mechanical alarm clocks, kitchen timers, mantel clocks and, until the 1970s, cheap watches now known as pin lever watches. It was patented by German watchmaker Georges Frederic Roskopf in 1867, suggested to Roskopf by Jules Grossmann.
The history of watches began in 16th-century Europe, where watches evolved from portable spring-driven clocks, which first appeared in the 15th century.
A mechanical watch is a watch that uses a clockwork mechanism to measure the passage of time, as opposed to quartz watches which function electronically via a small battery, or radio watches, which are quartz watches synchronized to an atomic clock via radio waves. A mechanical watch is driven by a mainspring which must be wound either periodically by hand or via a self-winding mechanism. Its force is transmitted through a series of gears to power the balance wheel, a weighted wheel which oscillates back and forth at a constant rate. A device called an escapement releases the watch's wheels to move forward a small amount with each swing of the balance wheel, moving the watch's hands forward at a constant rate. The escapement is what makes the 'ticking' sound which is heard in an operating mechanical watch. Mechanical watches evolved in Europe in the 17th century from spring powered clocks, which appeared in the 15th century.
A marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship's position by celestial navigation. It is used to determine longitude by comparing Greenwich Mean Time (GMT) and the time at the current location found from observations of celestial bodies. When first developed in the 18th century, it was a major technical achievement, as accurate knowledge of the time over a long sea voyage is necessary for navigation, lacking electronic or communications aids. The first true chronometer was the life work of one man, John Harrison, spanning 31 years of persistent experimentation and testing that revolutionized naval navigation and enabling the Age of Discovery and Colonialism to accelerate.
A chronometer is a specific type of mechanical timepiece. In Switzerland, only timepieces certified by the Contrôle Officiel Suisse des Chronomètres (COSC) may use the word certified chronometer or officially certified chronometer on them. Outside Switzerland, equivalent bodies, such as the Japan Chronometer Inspection Institute, have in the past certified timepieces to the same internationally recognised standards, although use of the term has not always been strictly controlled.
The history of timekeeping devices dates back to when ancient civilizations first observed astronomical bodies as they moved across the sky. Devices and methods for keeping time have since then improved through a long series of new inventions and ideas. Sundials and water clocks originated from ancient Egypt, and were later used by the Babylonians, the Greeks and the Chinese; medieval Islamic water clocks were unrivalled in their sophistication until the mid-14th century. Incense clocks, which may have been invented in India, were being used in China by the 6th century. The hourglass, one of the few reliable methods of measuring time at sea, was a European invention and does not seem to have been used in China before the mid-16th century.
In horology, a wheel train is the gear train of a mechanical watch or clock. Although the term is used for other types of gear trains, the long history of mechanical timepieces has created a traditional terminology for their gear trains which is not used in other applications of gears.
The Castle Combe clock in St. Andrew's Church, Castle Combe, Wiltshire, England was probably made in the late 15th century. It is faceless and strikes a bell in the church tower.
