The pallet fork is a component of the

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, an ...

of a

mechanical watch 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 watc ...

. The pallet fork and the lever form one component that sits between the escape wheel and the

balance wheel 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 ...

. Its purpose is to lock the escape wheel, and release it one tooth at a time at each swing of the balance wheel, and also give the balance wheel small pushes to keep it going. In early watches the pallet fork and the lever were made as separate components and joined together. In later watches they were made as a single component as shown in the picture. The combined component is often referred to simply as the "lever". In a straight line Swiss lever type escapement, the lever is shaped like a 'T' or an anchor, which gives this escapement its alternative name of anchor escapement. The lever is pivoted in the center; in operation it rocks back and forth.{{cite web , last = Odets , first = Walt , author-link = , title = The Escapement , work = Illustrated Glossary of Watch Parts , publisher = TimeZone.com , date = , url = http://www.timezone.com/library/wglossary/wglossary631692132071014935 , format = , doi = , accessdate = 2008-07-02 , archive-url = https://web.archive.org/web/20080630082138/http://www.timezone.com/library/wglossary/wglossary631692132071014935 , archive-date = 2008-06-30 , url-status = dead On the arms of the 'T' are angled surfaces called ''pallets'' which alternately engage the teeth of the escapement's ''escape wheel''. The central shaft of the lever ends in a fork, which gives pushes to the

's ''impulse pin'', which is set off center in a disk on the balance wheel's shaft. To reduce friction, the pallets are made of precisely shaped pieces of ruby jewel. The pallet which the teeth first contact is called the ''entry pallet'', while the other one is called the ''exit pallet''. Under the fork there is a projecting ''guard pin'' which passes through a notch in a separate ''safety roller'' disk on the balance shaft. In normal operation it doesn't have a function. Its purpose is to make sure the fork is in the right position to receive the impulse pin if a jar to the watch prematurely 'unlocks' the lever from the escape wheel. Mechanical

alarm clock An alarm clock (or sometimes just an alarm) is a clock that is designed to alert an individual or group of individuals at a specified time. The primary function of these clocks is to awaken people from their night's sleep or short naps; they ar ...

s and kitchen

timer A timer is a specialized type of clock used for measuring specific time intervals. Timers can be categorized into two main types. The word "timer" is usually reserved for devices that counts down from a specified time interval, while devices th ...

s use a less accurate form of the lever in which vertical metal pins are substituted for the pallet jewels. This is called a Roskopf or

pin-pallet escapement 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. ...

, and was previously used in cheap pin-lever watches.

Notes and references

Timekeeping components