Inhorology, amovement, also known as acaliber orcalibre (British English), is the mechanism of awatch ortimepiece, as opposed to thecase, which encloses and protects the movement, and theface, which displays the time. The term originated with mechanical timepieces, whoseclockwork movements are made of many moving parts. The movement of adigital watch is more commonly known as amodule.
In modern mass-produced clocks and watches, the same movement is often inserted into many different styles of case. When buying a qualitypocketwatch from the mid-19th to the mid-20th century, for example, the customer would select a movement and case individually. Mechanical movements get dirty and the lubricants dry up, so they must periodically be disassembled, cleaned, and lubricated. One source recommends servicing intervals of: 3–5 years for watches, 15–20 years forgrandfather clocks, 10–15 years for wall ormantel clocks, 15–20 years foranniversary clocks, and 7 years forcuckoo clocks, with the longer intervals applying to antique timepieces.[1]
A mechanical movement contains all the moving parts of awatch orclock except the hands, and in the case ofpendulum clocks, thependulum and driving weights. The movement is made of the following components:[2]
The wheels in a typical going train consist of a centre wheel, third wheel, and fourth wheel. A separate set of wheels, the "motion work", divide the minute hand's motion by 12 to move the hour hand. Watches are fitted with an additional set known as the "keyless work", which enables the hands to be set.
Watch movements come in various shapes to fit different case styles, such as round, tonneau, rectangular, rectangular with cut corners, oval and baguette, and are measured inlignes, or in millimetres. Each specific watch movement is called acaliber.[3] The movement parts are separated into two main categories: those belonging to theébauches and those belonging to theassortments.[2]
In watch movements the wheels and other moving parts are mounted between two plates, which are held a small distance apart with pillars to make a rigid framework for the movement. One of these plates, the front plate just behind the face, is always circular, or the same shape and dimensions as the movement. The back plate has various shapes:
| Mechanical movement,Deutsches Museum, München |
Mechanical watch movements are also classified as manual or automatic:
Additionally, a distinction is also sometimes made on whether or not the movement offershacking, allowing the second hand to be stopped.
Inhorology, "caliber" refers to the specific internal mechanism of a watch or clock, also known as a movement. Although the term originally was only used to refer to the size of a movement, it is now used to designate a specific model (although the same caliber can be used in many different watches or clocks). Different watch manufacturers tend to use their own identification system to number their calibers.[4]
