Origins of the automatic watch
Any typos are as a result of direct translation of the
original French.
The automatic watch, with the current direction of the
term, i.e. which goes simultaneously to the armage, was born in 1778.
It is at least what the oldest known descriptive document currently teaches us,
resulting from the French Academy of Sciences in Paris, by describing a part
deposited by the clock and watch maker inhabitant of Liège Hubert Sarton
(1748/1828).
This document, under the feather of the rapporteurs Roy and De Fouchy, analyzes
a watch which comprises a device with rotor, perfectly identical to all the
automatics bracelets built today.
5 parts of the time were found identical to the model presented.
The second known descriptive document goes back to 1780 with the patent
deposited by Recordon in England. No found part but all following automatics of
bracket was built on this model.
Breguet was without any doubt that which out of watch bracket improved to the
maximum the system, but no document is known on what it did at its beginning,
i.e. between 1775 and 1782.
Finally Perrelet, Gallmayer, and perhaps of others, had to consider the question
before 1778 without one being able to say what they did but certainly systems
which did not ensure walk at the same time as the armage.
The part of Sarton being the first of the kind to the statements of the
rapporteurs.
Show pocket "Subscription" Bréguet.
Faithful counterpart of a model carried out by A.-L. Bréguet at the end of the
XVIII E century.
It is equipped with an automatic movement and indicates the date, the phases of
the moon and the reserve of walk.
Automatic reassembly with jolts, repetition with fake
of the 1/4, indication of reserve of walk.
Finished August 1782, signed on movement:BREGUET in PARIS N° 1.8.82
Semicircular mass oscillating on a stud in the center
of the turntable (the rotor).
Realization of H. Sarton (source: "Perpetual with wheel of meeting" of
Joseph Flora, edition NEO)
The watch of pocket with automatic reassembly.
The figures below shows the mechanism of a watch of
pocket with automatic reassembly, for which a patent was granted in 1892.
The oscillating mass (A) swivels in A '.
It is under the action within the competence of recall U fixed at the bridge P.
With each jolt caused by a movement of the carrier, for example walk, the
oscillating mass moves in the direction of the arrow.
It transmits this movement to the "wheel of
armage" B, thanks to the "spring of armage" C, fixed at the
oscillating mass.
Then the spring U brings back the mass in the
position of the 1st figure.
At the time of the return of the mass oscillating to
its home position, a "snap ring" (C '), in catch with the teeth of the
wheel of armage B, prevents this wheel from retrogressing.
A "pin - stop" (T) limit displacements of the oscillating mass.
The rotation of the wheel of armage B is transmitted
to the barrel arbor by a spur gearing, not represented.
When the tension of the driving spring is maximum, by a clever device, pin Z
raises the snap ring.
The mass, actuated with each movement of the carrier,
involves the wheel of armage, but, the snap ring being moved away from the wheel
B, this wheel, after having advanced few teeth, moves back of the same quantity,
the spring of armage involving the wheel B then, as well behind as ahead.
When the spring of barrel is completely armed, the
movements of clock of the oscillating mass are without effect on the barrel
arbor.
But, when the watch works for a certain time and that the tension of the spring
decreases, pin Z releases the snap ring; this one comes again into contact with
the wheel B and the reassembly takes place like previously.
This part was provided with an indicator of
development of the spring and with a device making it possible to reassemble the
watch using a key, without actuating the gears of the automatic reassembly.
The watch - bracelet with automatic reassembly
The position of the wrist watch, placed at the wrist
of its owner, is very favorable to the automatic reassembly.
Swivelling in the center of the part, parallel to the
"movement", the oscillating mass of the wrist watch with automatic
reassembly does not move only when the carrier makes him undergo strong jolts,
but also at the time of simple movements of the arm or the wrist, and even,
under the action of gravity, when the watch is slightly tilted.
Generally, the oscillating mass of the watch with
automatic reassembly turns freely above the plan of the movement, side bridges.
It is generally semicircular; its axis of revolution is the prolongation of that
of the mobile of center.
Note:
So that the effect of reassembly is effective, it is essential that:
- The oscillating mass has the heaviest possible
rim, from where the use of gold, platinum or carbide of tungsten.
- By using a metal with high density (twice at least
that of brass), one produces a rotor of very appreciable dynamic quality in
spite of dimensions reduced, the esthetics of the watch gains there.
- The centre of gravity of the mass must be most
distant possible center.
- The oscillating mass must be free and never not to
touch the movement or limps it.
- The swivelling of the mass is well cleaned before
oiling it.
- If the swivelling of the mass is worn, the holes
of the stoppers having become oval, to replace them by new stoppers of
origin.
Oscillating mass with limited race
In certain models, the angular way of the mass is
limited by "springs shock absorbers" T.
The oscillating mass is then placed in order to be
actuated most frequently possible.
This favorable position corresponds, for the majority of the individuals, with
the average position of the front armlever during walk, the watch being placed
outside the wrist.
The angle which the oscillating mass in the watch
with "springs shock absorbers can traverse" is generally approximately
120 degrees.
The oscillating mass, actuated violently, comes to
strike against a "stop"; there is then a shock which, while being
repeated, can help the screws insufficiently blocked to unscrew itself.
All the screws of a watch with automatic reassembly
must thus be screwed well à.fond. It is also necessary to block the screws and
keys of dial.
Oscillating mass without limitation.
The oscillating mass turning without limitation is
generally named " rotor ". It can thus turn, in a direction or
the other, of 360 degrees or more.
Transmission of the movement of the oscillating
mass.
To transmit the movement of the mass oscillating to the ratchet, the three
systems most frequently met are as follows:
A pinion or "coils stage" B is fixed under the oscillating mass,
concentrically with its swivelling.
A pawl, known as "of armage" C swivels
under the oscillating mass or in a practised noyure to the mass.
A weak spring R maintains the end of the pawl in contact with the teeth of a
reference or "armage" B coils, turning freely, concentrically with the
swivelling of the oscillating mass.
The oscillating mass carries a "segment
toothed" B.
If one made operate the wheel of stage of the
oscillating mass, the toothed segment or the pawl directly the ratchet fixed
"at square" on the barrel arbor, the spring of barrel would oppose to
the oscillating mass a resistance much too large and the reassembly would not
take place.
One thus intercalates, between the oscillating mass
and the ratchet, a device made up generally by reducing "or"
reducing "wheel a".
Description of operation:
When the mass goes
up:
When the oscillating mass (A) moves in the direction of the arrow, the segment
toothed (B), fixed on this mass, involves the B' wheel in the direction of the
arrow.
- The ratchet B is
adjusted freely on the wheel B '.
- The pinion b' is interdependent of the ratchet.
Thanks to the pawl of armage C, maintained in contact
with the triangular teeth of the ratchet, by the spring R, the ratchet and its
pinion b' are involved, when the B' wheel turns in the direction of the arrow,
i.e. during the reassembly.
During the reassembly, the pawl It is raised in the passing of each tooth of the
wheel B "; this pawl prevents then the retreat of the wheel B ".
The pinion B ", interdependent of the wheel B ", gears with the wheel
D, which, during the automatic reassembly, turns in the direction of the arrow.
The pinion D, fixed on the wheel D, gears with the wheel of crown (E), which
transmits its rotation to the ratchet F.
Note:
To each displacement of the oscillating mass, the
ratchet F turns of an angular value lower than a step.
However, thanks to the detent pawl C ', the reducing wheel cannot move back. So
the pawl G remains in an unspecified position, after each action of the
oscillating mass.
When the mass does not go up:
The toothed segment involves the B' wheel in the
contrary direction of the needles of a watch.
The pawl of armage then makes simply "uncogging" on the teeth "Breguet"
of the wheel of armage B (ratchet).
During the manual reassembly:
During the manual reassembly of the watch, the wheel of crown, actuated by the
pinion of winder, obliges the ratchet F, the wheels D and B "to turn in the
direction indicated by the arrows. The detent pawl (C '), and the pawl of armage
C are raised.
Note:
The springs of the pawls of armage and stop of a
watch with automatic reassembly should neither too strong, nor be armed too
much.
Indeed, a spring of too strong detent pawl or too armed, causes an useless
resistance, during the automatic reassembly.
The surface quality of the nozzle of the pawls must of lines or burs but on the
contrary, softened or be polished.
The spring of barrel.
When the driving spring of a watch with automatic
reassembly is completely armed, its "overpressure should be avoided".
In other words, displacements of the oscillating mass, actuated with each
movement of the arm, must be without effect on the driving spring, when this one
reached its maximum tension, if not "rebat shows
it " then, the spring of barrel
continuing to be solicited by the automatic reassembly, will break or produce
disturbances in the automatic mechanism of reassembly.
One also avoids the "overpressure" within
the competence of barrel by generally providing the watches with automatic
reassembly with "slipping supports" known as "supports of
friction" or "springs of braking".
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