====== Movement ======
{{wst>image_r|Uhrwerk_Illustration1|Illustration}}
**Watch movement**

Drive mechanism of a [[watch]]

===== Who invented the watch movement? =====
The following discussion is intended to illustrate the basic principle of a mechanical watch. Strictly seen it does not apply to all types of watches and constructions, because there can be several differences. But the basic idea remains the same, because the watch has not been invented by a single person, but has continuously evolved, refined and improved over several centuries by a number of contributions. One can look at the watch, therefore, as a concerted development effort of all mankind.

===== The process of power transmission from winding to the hands =====
Consider first the image shown at the top right-hand corner. For reasons of clarity the drive mechanism is lined up from top to bottom - one wheel is driving the next.

With [[automatic]] watches the transmission begins at the [[rotor]], which makes use of the forces caused by movement changes at the wrist and transfers it to the [[mainspring]] and the [[barrel]]. Or in manual winding watches the force is generated by [[manual winding]].

===== The translation to the individual hand displays =====
{{wst>image_l|Uhrwerk_Illustration2|Illustration of the gear train}}
The [[going train]] translates the momentum into the different speeds Seconds, minutes, hours, etc. The picture on the left hand side shows the translation scheme of the gear train 

From the [[barrel]] (B) the force is transfered to the [[escapement wheel]] (E) as follows 

  *Z1 is the [[second wheel]], on the axis of which is the hour hand
  *Z3 is the [[third wheel]]
  *Z5 is the [[fourth wheel]], (possibly with the seconds hand)
  *All these wheels are usually riveted on their [[shaft]]s Z, Z2, Z4, Z6.

[[Escapement wheel]] and [[lever]] meet the back-and-forth swinging [[balance wheel]], which is pulsating at the [[balance spring]]. The principle of the [[escapement]] is explained below in more detail.

===== The movement construction =====
{{wst>image_l|Grundplatine|Main plate}}
In this picture a movement plate ([[main plate]]) is shown in which the gears of the [[gear train]] and [[barrel]], [[balance wheel]] and so on are fitted. To reduce the friction the [[shaft]]s of the wheels are fitted in so-called [[jewels]].

{{wst>image_r|Uhrwerk_Illustration4|Illustration of the order of the drive force}}
From a spatial perspective, as shown in the next picture, the drive mechanism is lined up from the [[barrel]] (left) to the [[balance wheel]] (on the right).

===== The oscillation system =====
{{wst>image_l|Uhrwerk_Illustration5|Oscillation and escapement system}}
The characteristic ticking of a mechanical watch is the acoustic feature of the oscillation and [[escapement]] system of a watch movement .

This oscillating system consists of the [[balance wheel]] [5], which is turning on the [[balance staff]], the [[balance spring]] [6], and a regulating device, usually called [[regulator]]. Hereby the oscillation of the balance spring can be precisely adjusted, so that the desired correct rate of the watch can be attained.

The exact rate is based on the maximum possible uniformity of the back-and-forth oscillation of the [[balance wheel]] [5], which must also be balanced as accurately as possible.

{{ https://www.uhren-wiki.com/images/Uhrwerk_Illustration6.gif}}

Without a steady, precise dosed energy supply this regulated organ however would cease to move. Therefore, it is constantly fed by the force coming from the [[barrel]] and via the [[gear train]] [1], in accordingly reduced doses. The [[escapement]] transfers this force via the [[escape wheel]] [2], the [[lever]] [3] and roller [4] further to the oscillation system. In a sophisticated flow by inhibiting and releasing the [[lever]] grips into the [[escape wheel]] in such a way that the movement is always pulsating in the same measure of time (see animation on the right hand side).

Hereby, depending on the oscillation frequency of the [[balance wheel]] (eg, 28,800 A/h), a precise base unit is given on which the rest of the arithmetic of gear ratios and hence the precision of the watch is based. Also the measuring accuracy of mechanical [[chronograph]]s directly depends on this background (for details see [[chronograph#The measuring accuracy of chronographs|The measuring accuracy of chronographs]]).

===== Additional information =====
  *[[Raw movement]] ([[ebauche]])
  *[[Regulation]]
  *[[Deviation]]
  *[[Chronometer]]
  *[[Tourbillon]]
  *[[Flying tourbillon]]

===== Literature =====
  *[[Das ZEITGEFÜHL-Uhrenbuch]]; Author [[Gerd-Lothar Reschke]]; ISBN 3-938607-61-0


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