Barrel (horology)

Last updated
Watch going barrel Watch mainspring barrel.png
Watch going barrel

Used in mechanical watches and clocks, a barrel is a cylindrical metal box closed by a cover, with a ring of gear teeth around it, containing a spiral spring called the mainspring, which provides power to run the timepiece. [1] The barrel turns on an arbor (axle). The spring is hooked to the barrel at its outer end and to the arbor at its inner end. The barrel teeth engage the first pinion of the wheel train of the watch, usually the center wheel. [2] Barrels rotate slowly: for a watch mainspring barrel, the rate is usually one rotation every 8 hours. This construction allows the mainspring to be wound (by turning the arbour) without interrupting the tension of the spring driving the timepiece.

Contents

Types

Plain barrel
I.e. without teeth, used in fusee watches and clocks. A chain, or cord, was wound around the plain barrel, connecting it to the fusee.
Going barrel
The form used in modern watches, is wound by turning the arbor and drives the watch movement by a ring of teeth around the barrel. This enables the mainspring to continue running the watch while it is being wound. Invented by Jean-Antoine Lépine.
Hanging barrel
A version of the going barrel that to save space is supported by the movement only at its upper end.
Motor, or safety, barrel
Used in pocket watches around 1900, a reverse variant of the going barrel in which the spring is wound by turning the barrel, and turns the watch movement by the central arbor. The purpose of this arrangement was that if the spring breaks, destructive recoil forces would not be applied to the vulnerable gear train.

Related Research Articles

<span class="mw-page-title-main">Watch</span> Personal timepiece

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.

<span class="mw-page-title-main">Escapement</span> Mechanism for regulating the speed of clocks

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.

<span class="mw-page-title-main">Pocket watch</span> Watch made to be carried in a pocket

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.

<span class="mw-page-title-main">Movement (clockwork)</span> Mechanism of a watch or clock

In horology, a movement, also known as a caliber or calibre, 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.

<span class="mw-page-title-main">Mainspring</span> Spiral torsion spring of metal ribbon used as a power source in mechanical watches and clocks

A mainspring is a spiral torsion spring of metal ribbon—commonly spring steel—used as a power source in mechanical watches, some clocks, and other clockwork mechanisms. Winding the timepiece, by turning a knob or key, stores energy in the mainspring by twisting the spiral tighter. The force of the mainspring then turns the clock's wheels as it unwinds, until the next winding is needed. The adjectives wind-up and spring-powered refer to mechanisms powered by mainsprings, which also include kitchen timers, metronomes, music boxes, wind-up toys and clockwork radios.

<span class="mw-page-title-main">Verge escapement</span> Early clock mechanism

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'. 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.

<span class="mw-page-title-main">Balance wheel</span> Time measuring device

A balance wheel, or balance, 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 the balance wheel. Each swing of the wheel 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 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.

<span class="mw-page-title-main">Lever escapement</span>

The lever escapement, invented by the English 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.

<span class="mw-page-title-main">Striking clock</span> Clock that sounds the time with a bell or gong

A striking clock is a clock that sounds the hours audibly on a bell, gong, or other audible device. In 12-hour striking, used most commonly in striking clocks today, the clock strikes once at 1:00 am, twice at 2:00 am, continuing in this way up to twelve times at 12:00 mid-day, then starts again, striking once at 1:00 pm, twice at 2:00 pm, up to twelve times at 12:00 midnight.

<span class="mw-page-title-main">Fusee (horology)</span> Mainspring force equalizing pulley in timepieces

A fusee is a cone-shaped pulley with a helical groove around it, wound with a cord or chain attached to the mainspring barrel of antique mechanical watches and clocks. It was used from the 15th century to the early 20th century to improve timekeeping by equalizing the uneven pull of the mainspring as it ran down. Gawaine Baillie stated of the fusee, "Perhaps no problem in mechanics has ever been solved so simply and so perfectly."

<span class="mw-page-title-main">Balance spring</span>

A balance spring, or hairspring, is a spring attached to the balance wheel in mechanical timepieces. It causes the balance wheel to oscillate with a resonant frequency when the timepiece is running, which controls the speed at which the wheels of the timepiece turn, thus the rate of movement of the hands. A regulator lever is often fitted, which can be used to alter the free length of the spring and thereby adjust the rate of the timepiece.

<span class="mw-page-title-main">History of watches</span> Aspect of history

The history of watches began in 16th-century Europe, where watches evolved from portable spring-driven clocks, which first appeared in the 15th century.

<span class="mw-page-title-main">Automatic watch</span> Timekeeping device that is driven by a spring that winds by motion of the wearer.

An automatic watch, also known as a self-winding watch or simply an automatic, is a mechanical watch where the natural motion of the wearer provides energy to wind the mainspring, making manual winding unnecessary if worn enough. It is distinguished from a manual watch in that a manual watch must have its mainspring wound by hand at regular intervals.

<span class="mw-page-title-main">Skeleton clock</span> Clocks with visible inner workings

A skeleton clock is any clock or wristwatch, though typically mechanical in nature, in which the parts that usually conceal the inner workings of the mechanism have been removed or significantly modified so as to display these inner parts.

<span class="mw-page-title-main">Power reserve indicator</span> Watch complication

A power reserve indicator is a complication of the watch, which is designed to show the amount of remaining stored energy. The power reserve indicator indicates the tension on the mainspring at any particular moment.

In mechanical horology, a remontoire is a small secondary source of power, a weight or spring, which runs the timekeeping mechanism and is itself periodically rewound by the timepiece's main power source, such as a mainspring. It was used in a few precision clocks and watches to place the source of power closer to the escapement, thereby increasing the accuracy by evening out variations in drive force caused by unevenness of the friction in the geartrain. In spring-driven precision clocks, a gravity remontoire is sometimes used to replace the uneven force delivered by the mainspring running down by the more constant force of gravity acting on a weight. In turret clocks, it serves to separate the large forces needed to drive the hands from the modest forces needed to drive the escapement which keeps the pendulum swinging. A remontoire should not be confused with a maintaining power spring, which is used only to keep the timepiece going while it is being wound.

<span class="mw-page-title-main">Mechanical watch</span> Type of watch which uses a clockwork mechanism to measure the passage of time

A mechanical watch is a watch that uses a clockwork mechanism to measure the passage of time, as opposed to quartz watches which function using the vibration modes of a piezoelectric quartz tuning fork, 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.

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.

<span class="mw-page-title-main">Jean-Antoine Lépine</span> French master clockmaker and watchmaker

Jean-Antoine Lépine was a French watchmaker. He contributed inventions which are still used in watchmaking today and was amongst the finest French watchmakers, who were contemporary world leaders in the field.

<span class="mw-page-title-main">Stackfreed</span> Clockwork

A stackfreed is a simple spring-loaded cam mechanism used in some of the earliest antique spring-driven clocks and watches to even out the force of the mainspring, to improve timekeeping accuracy. Stackfreeds were used in some German clocks and watches from the 16th to the 17th century, before they were replaced in later timepieces by the fusee. The term may have come from a compound of the German words starke ("strong") and feder ("spring").

References

  1. Hebert, Luke (1856). The Engineer's and Mechanic's Encyclopædia, Comprehending Practical Illustrations of the Machinery and Processes Employed in Every Description of Manufacture of the British Empire, Etc. p. 703.
  2. Hood, Grant (1904). Modern Methods in Horology. Kansas City Jeweler and Optician. p. 44.