Thursday, September 01, 2005


Device of the escapement (s.) transmitting part of the motive force to the balance (s.), in order to maintain the amplitude of oscillations unchanged by freeing a tooth of the escape wheel at one time.
Supporting element of bridges (s.) and other parts of a movement (s).
Combines with a wheel and an arbor (s.) to form a gear (s.). A pinion has less teeth than a wheel and transmits motive force to a wheel. Pinion teeth (normally 6 to 14) are highly polished to reduce friction to a minimum.
End of an arbor (s.) turning on a jewel (s.) support. As their shape and size can influence friction, the pivots of the balance-staff are particularly thin and, hence, fragile, so they are protected by a shockproof (s.) system.
Said of a metal treated by a galvanizing procedure in order to apply a slight layer of gold or another precious metal (silver, chromium, rhodium or palladium) on a brass or steel base.
A synthetic resin used for watch crystal.
Distinction assigned by the Canton of Geneva to movements produced by watchmaker firms of the Region and complying with all the standards of high horology with respect to craftsmanship, small-scale production, working quality, accurate assembly and setting. The Geneva Seal is engraved on at least one bridge and shows the Canton’s symbol, i.e. a two-field shield with an eagle and a key respectively in each field.
Duration (in hours) of the residual functioning autonomy of a movement after it has reached the winding peak. The duration value is displayed by an instantaneous indicator: analog (hand on a sector) or digital (through a window). The related mechanism is made up of a series of gears linking the winding barrel and hand. Recently, specific modules were introduced which may be combined with the most popular movements.
The pulsimeter scale shows, at a glance, the number of pulse beats per minute. The observer releases the chronograph hand when starting to count the beats and stops at the 30th, the 20th or the 15th beat according to the basis of calibration indicated on the dial.
Mechanical element mounted on a case (s.) for the control of specific functions. Generally, pushers are used in chronographs (s.), but also with other functions.
Abbreviation of Physical Vapor Deposition, a plating process consisting of the physical transfer of substance by bombardment of electrons.
Made up by balance (s.) and balance spring (s.), governing the division of time within the mechanical movement, assuring its regular running and accuracy. As the balance works like a pendulum, the balance spring’s function consists of its elastic return and starting of a new oscillation. This combined action determines the frequency, i.e. the number of vibrations per hour, and affects the rotation speed of the different wheels. In fact the balance, by its oscillations, at every vibration (through the action of the pallets), frees a tooth of the escape wheel (s. Escapement). From this, motion is transmitted to the fourth wheel, which makes a revolution in one minute, to the third and then the center wheel, the latter making a full rotation in one hour. However, everything is determined by the correct time interval of the oscillations of the balance.
Regulating the functioning of a movement by lengthening and shortening the active section of the balance spring (s.). It is positioned on the balance-bridge and encompasses the balance spring with its two pins near its fixing point on the bridge itself. By shifting the index, the pins also are moved and, by consequence, the portion of the balance spring capable of bringing the balance back is lengthened or shortened by its elastic force. The shorter it is, the more reactive it tends to be and the more rapidly it brings the balance back and makes the movement run faster. The contrary happens when the active portion of the balance spring is lengthened. Given today’s high frequencies of functioning, even slight index shifts entail daily variations of minutes. Recently, even more refined index-regulation systems were adopted (from eccentric (s.) to micrometer screws (s.)) to limit error margins to very few seconds per day.
Mechanism indicating time by acoustic sounds. Contrary to the watches provided with en-passant sonnerie (s.) devices, that strike the number of hours automatically, repeaters work on demand by actuating a slide (s.) or pusher (s.) positioned on the case side. Repeaters are normally provided with two hammers and two gongs: one gong for the minutes and one for the hours. The quarters are obtained by the almost simultaneous strike of both hammers. The mechanism of the striking work is among the most complex complications.
Said of a hand (s.) that, instead of making a revolution of 360?before starting a new measurement, moves on an arc scale (generally of 90?to 180? and at the end of its trip comes back instantaneously. Normally, retrograde hands are used to indicate date, day or month in perpetual calendars, but there are also cases of retrograde hours, minutes or seconds. Unlike the case of the classical indication over 360? the retrograde system requires a special mechanism to be inserted into the basic movement.
In automatic-winding mechanical movements the rotor is the part that, by its complete or partial revolutions and the movements of human arm, allows winding of the mainspring (s.).