A self-winding watch is a mechanical watch whose reassembly is carried out by a mechanism that allows to reset the spring of the barrel during the wearing of the watch. Thus the movements carried out by the wearer store energy which activates the movement of the watch. An automatic watch has a power reserve , which varies according to the model, before stopping. People who wish to keep several watches in operation without having to wear them can make use of a clock .
A fully automatic watch is always less precise than a quartz watch but often loves more lovers of mechanical and watchmaking.
Historians are not unanimous concerning the origin of this invention 1 , 2 . For some, it was the Swiss Abraham Louis Perrelet who invented this device in 1777 3 , for others it was the Liégeois Hubert Sarton in 1778 with a winding with rotor. 4
This device was not used heavily with the advent of wristwatches in the early xx th century. Nowadays, manual winding has not disappeared and the majority of high-end mechanical watches use this reassembly device.
There are several mechanisms of automatic winding, but the most widespread is the winding with rotor . The principle is quite simple. First of all, a rotor rotates on itself while driving a set of gears which serves as a mechanical reducer . By decreasing the speed of rotation to increase the torque , the spring of the barrel can be raised. Moreover, this set of gears allows the rotor to raise the watch independently of the direction of rotation by means of an internal snap mechanism which causes the differential which multiplies the rotation speed to always rotate in the same direction.
In order to benefit from the precision of the quartz control, there is a similar watch, in which the oscillations of the rotor are amplified by a set of gears, in order to actuate a generator which recharges the battery of the watch. This is the case for example of the Kinetic system of the watchmaker Seiko , it keeps the watch on time for four years.
Notes and references
- ↑ article by Grégory Pons in Business Watches – The international letter of the watch markets of 19 December 2006. [ Archive ]
- ↑ Site of Joseph Flores , who questions the attribution of the title “inventor of automatic watches” to Abraham Perrelet. [ Archive ]
- ↑ Article Abraham Louis Perrelet on hautehorlologie.org . [ Archive ]
- ↑ ” Automatic rotor devices “ [ Archive ]
- Joseph Flores, Perpetuals with a wheel of encounter or Automatic watches, a page of history: analysis of a document of the French Academy of 1778 and its historical consequences , Besançon, Néo,, 160 p. ( ISBN 2-914-74102-2 , record BNF n o FRBNF37718591 )
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