Glossary

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Regulateur
A dial constellation for easier reading: seconds and hours are decentral, minutes are central. Frequently seen in grandfather clocks which were often used by watchmakers as orientation.

Repeater
Watch that strikes the hours by means of a mechanism operated by a push-piece or bolt. There are various types of repeaters. Quarter-repeater: sounding a low note for the hours and a "ding-dong" for each of the quarters; Five-minute repeater: striking the hours, quarters and five-minute periods after the quarter; Minute-repeater: striking the hours, quarters and minutes; Grande sonnerie (grand strike): striking the hours and quarters automatically and repeating when a push-piece is pressed down; Chiming repeater: in which the quarters are struck on three or four gongs of different pitch.

Rotor
Half-disc of heavy metal, which is made to rotate inside the case of an automatic watch by the energy produced by the movements of the wearer's arm. Its weight tends always to bring it back to the vertical position. Demultiplied by a specially designed device, its rotations continually wind the mainspring of the watch.

Rounding off
Pivots whose faces rub against the bearing surfaces are rounded off to reduce friction, so that there is only a load at one point on a bearing when it is put under vertical pressure.

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Screw balance
A balance where the balance rim with inlaid screws is counterbalanced to generate a weight balance.

Second
Basic unit of time (abbr. s or sec), corresponding to one 86,000th part of the mean solar day, i.e. the duration of rotation, about its own axis, of an ideal Earth describing a circle round the Sun in one year, at a constant speed and in the plane of the Equator. After the Second World War, atomic clocks became so accurate that they could demonstrate the infinitesimal irregularities (a few hundreths of a second per year) of the Earth's rotation about its own axis. It was then decided to redefine the reference standard; this was done by the 13th General Conference on Weights and Measures in 1967, in the following terms: «The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the fundamental state of the atom of caesium 133». Conventionally, the second is subdivised into tenths, hundredths, thousendths (milliseconds), millionths (microseconds), thousand-millionths (nanoseconds) and billionths (picoseconds).

Shock Absorber
Resilient bearing which, in a watch, is intended to take up the shocks received by the balance staff and thus protects its delicate pivots from damage.

Skeleton
Skeleton watch: watch in which the case and various parts of the movement are of transparent material, enabling the main parts of the watch to be seen.

Solar finish
Decorations created on the surfaces of the metal parts (wheels, dials) by means of polishing which, when reflecting light, create the impression of a shining sun.

Striking-work, Striking-Mechanism
In a watch or clock, automatic or hand-operated mechanism that strikes the hours, etc, or rings an alarm-bell (v. repeater).

Swan-neck fine adjustment
An adjustment mechanism for setting the precise motion of the watch whereby the righting moment for the regulator pointer is generated by a spring for precise adjustment. This spring is swan-neck shaped.