Indication of the date may be either analogue by means of a hand or digital by means of a printed disk. The hand or ring rotates once about its own axis every 31 days. Each night (near midnight), the dial-train (motion-work) propels them one increment further along. In mechanical watches, the date display requires manual adjustment at the end of each month which has fewer than 31 days. Adjustment is usually performed either by depressing a push-piece in the edge of the case, via the crown and dial-train (rapid adjustment via forward or backward motion of the hand between circa 10:00 p.m. and midnight). or with the help of a special rapid adjustment button situated directly atop the winding-crown. This button brought into its intermediate position and turned until the date display shows the correct date.
Daily deviation between 0 and +15 seconds. These are the tolerances accepted by Chronoswiss.
The time is expressed in the form of numerals.
A convex pane of transparent material (usually artificial sapphire) covering a watch’s dial.
French term for an incomplete watch-movement lacking its escapement and/or mainspring.
A colored or transparent layer of vitreous material which protects or decorates its metal substrate. From a chemical point of view, enamel is a special type of glass which can be colored white by mixture of antimony, zircon oxide, titanium dioxide or colored other hues by mixture of other coloring agents. The glassy material melts at 1,200º Celsius and is subsequently quenched. The resulting grains are ground to a powder together with coloring agents. Finally, the enamel is either brushed or sprayed, or else the object is dipped into an enamel bath, so that the well-cleansed metal substrate is completely covered with enamel, which is then heated in a special kiln to between 800º and 900º Celsius.
The engraving of interwoven geometric forms (guilloché) onto a metal surface is accomplished mechanically by an artisan who guides an engraving tool equipped with various mechanical gears.
Energy from the mainspring is conveyed through the gear-train to the escapement, which further conveys this energy to the oscillating system (balance, balance-spring) of a watch. It consists of the escape-wheel and its pinion, the lever with its two pallets, the fork of the anchor, the guard-pins and the table-roller with the ellipse and the safety-roller. The two rollers are attached to the balance-staff and move to and fro in harmony with the beats of the balance. Swiss lever escapement. The escapement of a mechanical wristwatch performs extraordinarily demanding work: if the frequency of the balance is 28,800 beats per hour, then it allows the gear-train to advance 691,200 times every 24 hours. Within four years’ time, this amounts to more than one billion impulses which are conveyed through the escapement. This work is six times more grueling than that performed by the human heart.
(No English equivalent). An enterprise in the watchmaking industry which occupies itself exclusively with the assembly (remontage) of watches ébauches the établisseur purchases from specialized suppliers.
(French: water-resistant). One thing should be carefully considered: information about the degree of water-resistance is based on momentary measurements and is not guaranteed to be valid for the lifetime of the watch. Manipulations on the case, aging of the insulating material or severe variations in temperature (e.g. ending a sunbath with a plunge into cold water) can allow water to penetrate into even the most water-resistant watch case and can necessitate costly repairs. The recommendation in the owner’s manual, which suggests that water-resistant watches should be competently checked once each year, ought to be taken seriously.
A mechanism for finely adjusting the daily deviation of rate. There are various mechanisms to accomplish this adjustment, e.g. the elegant swan’s neck mechanism or the one with an eccentric screw. A common but erroneous opinion is that fine regulation can lead to greater precision. The fact is that an ordinary regulator (index) can be used to exactly regulate a watch, although this task requires a great deal of manual dexterity.
An additional hand affixed to the arbor of the wheel which propels the seconds-hand. A fly back hand makes it possible to simultaneously time the duration of two or more sequences if they both begin at the same moment but last for unequal lengths of time. This is the situation, for example, in athletic races. The fly back hand. is coupled to the chronograph hand via a complex and costly mechanism. A special push-piece enables the user to momentary arrest the motion of the fly back hand (e.g. to read an intermediate time) and then instantaneously advance it to overlap the chronograph hand, which has continued to move uninterruptedly.
Anzahl der Halbschwingungen/Sekunde (Maßeinheit = Hertz). Ein Sekundenpendel vollzieht eine Schwingung in 2 Sekunden, deshalb beträgt die Frequenz 1/2 Hertz (Hz). Eine Armbanduhr, deren Unruh 18.000 Halbschwingungen/Stunde vollzieht, besitzt eine Frequenz von 2,5 Hz. Schnellschwinger mit 28.800 Halbschwingungen/Stunde eine Frequenz von 4 Hz.
A complete calendar showing the current day, date and month. Manual adjustment of the date and month are required at the end of each month which has fewer than 31 days.