Microtor Technology by Universal Genève - Universal Geneve

Microtor Technology by Universal Genève

Microtor

1955
Microtor UG 66

2006
Microtor UG 100

S
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elf-winding watches
The first watch automatically wound by means of
a central oscillating weight appeared in the latter
half of the 18 th century, in Le Locle. It stemmed
from the ingenious work of watchmaker Abraham-Louis
Perrelet (1729-1826), who had
observed that the rotation of the oscillating
weight generated sufficient energy to wind the
mainspring.
The first self-winding wristwatch was developed
by Englishman John Harwood, who filed a patent
for it in Switzerland in 1932. The oscillating
weight, which was wound in one direction only,
described a 130° arc of a circle. The disadvantage of
this watch was that it could not be wound by hand.
Ever since, this major technical innovation has
been constantly perfected, driven by an ongoing
quest for miniaturisation and precision.
Universal Genève watchmakers were pioneers in
the development of self-winding movements,
particularly due to the integrated micro-oscillating
weight that made them extremely thin and
uniquely elegant.
Universal Genève assembly workshop 1940
In the late 1940s, at a time when Universal
Genève was still known as Universal Watch
Factory, Perret & Berthoud Ltd (a name linked to
the names of its founders), the watchmakers
Universal Genève trademarks 1936, 1940, 1957
of the Manufacture presented a men’s self-winding
wristwatch equipped with Calibre UG 138. The
oscillating weight, located at the centre of the
movement, made a partial revolution of 315° and
was limited along its trajectory by two cylindrical
buffer-springs placed on the edge of the mainplate.
Calibre UG 138, displaying the hours, minutes and
small seconds at 6 o’clock, measured 28.20mm in
diameter and was 4.85mm thick. The balance
oscillated at a frequency of 18,000 vibrations per
hour. The first caliber was to be followed in the
early 50s by two movements featuring the same
technical characteristics : the 5.55mm thick
Calibre UG 138.SS-SC with centre seconds; and
the 6mm thick Calibre UG 138.C.C complete with
date disc and small seconds at 6 o’clock, which
drove the “Monodatic” model.
Calibre UG 138.SS-SC

The chief assets of this calibre were the antimagnetic
balance-spring and balance (the latter
being of the bimetallic glucydur type with
screws), as well as the balance-cock fitted with
a fine-adjustment system and Incabloc shockabsorbers.
For the version with a date display,
since the date-jump could be adjusted in one
direction only, the time could thus be set counterclockwise
without making the date jump, which
was not the case with previous Calibres. The 40hour
power reserve was perfectly respectable at
the time. The movement was equipped with 17
top-quality jewels. The setting-lever was connected
to an arbor that need only be pressed in order
to pull out the winding-stem.
On November 8 th 1952, the Universal Perret &
Berthoud Watch Manufacture in Geneva filed
patent n 0 308028, published on September 1 st
1955, for a self-winding device with double effect
via a rotating oscillating weight, which was to
serve as a model for the construction of the
Microtor. The rotating oscillating weight transmitted
its energy to the driving organ of the watch via
a loose-wheel coupling clutch, characterised by
an oscillating weight connected to an organ driving
two cams - themselves connected but operating
independently of each other. This system meant
the watch could be automatically wound in both
directions of the oscillating weight rotation.
Patent n° 308028
In 1954, watch designer Gérald Genta created
the famous Polerouter (Polarouter), which was
to enjoy worldwide success. Equipped with
Calibre UG 138 SS, this watch accompanied the
crew of the SAS Scandinavian Airlines System
1954 - Polerouter
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Company on the first ever flight from Europe to
the United States via the polar circle.
Building on its success, Universal changed its
name to Manufacture des Montres Universal,
Perret Frères SA in Carouge-Geneva, and opened
its new operational centre on the Place d’Armes in
Carouge, while keeping its historical premises on
the Rue du Rhône as a showroom.
icrotor watches
On May 27th 1955, Universal Genève filed patent
n° 329805 with the Intellectual Property Bureau.
Published on June 30th Universal Genève showroom on the quaysides of the Rhône - Geneva
Mr Perret & Mr Amann (Director SAS Geneva)
M
1958, it protected an
ultra-thin self-winding watch comprising a microoscillating
weight with an off-centred rotation
axis: the first Microtor Calibre UG 215 produced
by Universal Genève was born.
Universal Genève Headquarters - Carouge
Patent n° 329805

Calibre UG 215-2
This major technological innovation was made
possible by the constant improvement of the
quality of components supplied by the Swiss
watch industry and by the gradual miniaturisation
of these parts during the 1940s and 1950s.
The technical solution lay in the perfect proportions
of the frequency-reduction mechanisms of the
automatic winding system. The micro-oscillating
weight, pivoting in both directions and coupled to a
large-diameter barrel, ensured a power reserve of
almost 48 hours.
Calibre UG 215 displayed only the hour and
minutes, measured 28mm in diameter and was
4.10mm thick. Its balance oscillated at 18,000
vibrations per hour.
In 1958, Büren Watch Co SA (Von Büren Watch
Co., which disappeared in the 1970s), a Swiss-
German company extremely active in research
and development of new calibres, filed patent
n° 345849 for a micro-oscillating weight nicknamed
Super-Slender, similar to the one devised
by Universal Genève in 1955. Since the
Geneva-based Manufacture had filed its patent
just one month after that filed by Von Büren, the
two companies had to reach an agreement in
order to separately exploit this remarkable
invention, which they would subsequently place
at the disposal of the greatest names in Swiss
watchmaking.
In the 1950s, Universal Genève continued
developing the Microtor-based technology and
presented many new models that would ensure
its international success and reputation.
The Microtor technology was once again improved
and on January 30 th 1957, Universal Genève
filed patent n° 330900, published on August 15 th
1958, for a self-winding movement with central
seconds wheel and pinion, comprising a rotating
oscillating weight integrated within the movement
and featuring an axis off-set in relation to the
movement. The micro-oscillating weight was
positioned in the space left free by the barrel and
balance, and turns in bearings carried exclusively
by a bridge.
The UG 215 family of Calibres comprised the same
technical characteristics as the UG 138 Calibres,
meaning a balance frequency of 18,000 vibrations
per hour and a total diameter of 28mm, but now
had 28 jewels. The Calibre UG 215 was a threehand
movement with central seconds. The UG
215.1 version, which was 5.15mm thick, featured
central hour, minute and seconds hands along with
a date disc. Calibre UG 215.2 was endowed with
the same functions as Calibre UG 215.1, but was
0.45mm slimmer, at 4.70mm.
Patent n° 330900
The qualities and improvements embodied in
this calibre compared with Calibre UG 138 comprise
a simplification of the self-winding system,
reduced thickness, including for the date disc
version, and enhanced comfort on the wrist,
since the wearer no longer felt the shocks induced
by the oscillating weight; there was however
no fine adjustment.
Once again, Universal Genève was to present an
invention that would represent a landmark in
watchmaking history, since similar movements
are still widely used in the construction of many
self-winding Calibres. Patent n° 333993 was filed
on December 29 th 1956 and published on
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December 31 st 1958, for the creation of a watch
model equipped with both a hand-wound and a
self-winding system, and built in such a way that
these two systems worked independently of each
other. This new construction for a Microtor was
characterised by a pinion fixed to the barrel-arbor
by two discs, each fixed to one of the bases of the
pinion, on the same plane as the latter, and by
two superimposed wheels placed between these
discs and each linked to one of the winding
mechanisms. Each of these wheels is driven by
the adjacent disc and carries at least one coupling
organ designed to mesh with the pinion. These
coupling organs rotate in the same direction.
Constantly in quest of perfection, watchmakers
were soon to replace Calibre UG 215.2 by Calibre
UG 218.2, measuring 28mm in diameter and
4.70mm thick, equipped with a date indication.
This movement was to be used in assembling
Polerouter Date watches.
The main improvement featured in
Calibre UG 218 compared with its predecessor,
the UG 215, was the fine
Patent n° 333993
adjustment, since the balance-cock was equipped
with a micrometrical adjustment screw, thereby
providing enhanced precision and facilitating
adjustment.
Calibre UG 1-69
On March 26 th 1956, under patent n° 336013,
published on March 4 th 1959, Universal Genève
filed an additional patent n° 329805, covering a
central wheel and pinion carrying the minute
hand composed of a single pinion simultaneously
meshing with two coaxial wheels, the first leading
to the second that in turn transmits the movement
to the balance.
Calibre UG 68 (or UG 1-68), which was 4.10mm
thick, drove central hour, minute and seconds
hands. As the direct successor to Calibre UG 218,
this movement had 28 jewels and a frequency of
18,000 vibrations per hour.
While Calibre UG 69 (or UG 1-69) featured the
same technical characteristics as Calibre
UG 68, it was also equipped
Golden Classique 69

with a date disc, taking the total movement thickness
to 4.70mm, like its forerunner the UG 215.
Nonetheless, the geometry of its micro-rotor had
been transformed.
Calibres UG 68 and UG 69 underwent many
improvements during the actual production process,
including a “stop oil” chemical treatment
generally referred to as “epilame coating”. The
latter modifies the surface tension of the part
thus treated, thereby preventing oils from creeping,
ensuring lasting lubrication of the gearwheels
and thus reducing the frequency of
movement overhauls (technical note n° 76 dated
07/12/1967). These two Calibres also featured
Polerouter Sub
an excellent 55-hour power reserve. There was
also a Polerouter Sub with two crowns equipped
with Calibre 68, but with no date display.
For reasons related to rationalising production of
the balance-cock, the UG 1-68 and 1-69 versions
had no fine adjustment but were still fitted with
the mobile balance-spring stud-holder (source :
catalogue of old UG Calibres).
At the 1966 Basel Show, Universal Genève presented
a new range of refined and elegant watches
named Golden Shadow, all driven by the world’s
thinnest self-winding Microtor movement. It was to
enjoy considerable popularity.
Golden Shadow
Over 250 variations of the Golden Shadow were
created to highlight its extreme slenderness,
including the gold-plated Gilt Shadow or the steel
White Shadow.
The saga of Shadow watches equipped with
Calibres 66 and 67, and of their subsequent
technical developments, was to last from the
mid-1960s through to the early 1990s.
The ultra-thin self-winding Microtor Calibre UG 66
displayed the hours and minutes only, and featured
a diameter of 28mm and an exceptionally
diminutive thickness of 2.50mm. Its balance
oscillated at 19,800 vibrations per hour.
Calibre UG 1-66
Among the other particularly important features
were the self-compensating monometallic balance
and spring operating at 19,800 vibrations/hour
and equipped with a system designed
to absorb shocks to the balance pivots, referred to
at the time in French as “super-choc Incabloc”.
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The self-winding system consisted of a ball-bearing
device for the oscillating weight and of a reverser
with three ball-bearing devices (technical note n°
26) that reduced friction, thereby improving the
winding of the Calibre.
The line of UG 66 Calibres developed steadily
throughout the 1960s and comprised different
variations such as Calibre UG 1-67 displaying the
hours, minutes and date and measuring 3.10mm
in all.
Calibre UG 1-67
Calibre UG 66 became UG 1-66 after the addition
of a coupling clutch doing away with the
rotation of the winding wheel and pinion when
the watch was wound by hand, and thus avoiding
wear of the lower winding wheel (technical note
n° 75 dated 17/10/1967).
Calibres UG 1-66 and 1-67 became UG 2-66
and 2-67 respectively, after the classic pin-type
method of securing the balance-spring stud was
replaced by a new cementing system (technical
note n° 104).
Calibre UG 2-67
Calibre UG 2-66
On February 2 nd 1963, the Geneva-based
Manufacture filed patent n° 388195, published
on August 14 th 1964, covering the development
of a bidirectional oscillating weight thanks to a
reverse system composed of a plate pivoting in
the frame of the watch and carrying two pivoting
intermediate wheels mounted on ball-bearing
devices.
In the 1970s, Universal Genève watchmakers
continued to fine-tune the line of ball-bearing
mounted micro-rotor movements and presented
two new Calibres, UG 71 and UG 72, which were
used in the Polerouter III watch lines.
Patent n° 388195
These two Calibres shared the same characteristics
as the family of UG 66 Calibres, albeit with a
smaller overall diameter of 27mm instead of
28mm, and a new type of balance guaranteeing
an oscillation frequency of 21,600 vibrations per
hour (as did UG 215-9, UG 215-97 and UG 218-9).
The construction principle of Calibre UG 71 was
nonetheless reminiscent of that of the UG 69
Calibre and did not stem directly from the UG 66
Calibres. Calibre UG 71 featured centre seconds

and a date display and was 3.90mm thick, whereas
Calibre UG 72 also showed the days of the
week on a second counter, increasing the total
movement thickness to 4.60mm.
he renewal of the Microtor
At the 2006 edition of the Basel Show (now named
Baselworld) and after two years of intensive
research and development, Universal Genève
sprung a surprise by presenting a 111/2 T
lignes
Microtor Calibre UG 100 movement stemming
from an entirely new conception, in keeping with
the traditions of the great Swiss Watch
Calibre UG 71 Manufactures.
Calibre UG 72
Polerouter
Calibre UG 100
In developing this new Calibre, one of the main
issues was to resolve the tough question of the
(central) deadbeat seconds display which, on the
previous Calibres and especially the UG 66
movements, was derived from a small seconds
display at 3 o’clock via a complication plate. The
movement construction thus needed to be entirely
redesigned and the position of the going train had
to be modified in order to put the seconds back
in the centre by means of a gear system involving
two third wheels.
The construction principle consisting of the two
third wheels first of all made up for gearing play
and also alleviated the jerking motion resulting by
the seconds wheel. This solution also had the
advantage of avoiding the use of a friction spring,
such as is generally present in the construction of
most Calibres. The absence of a friction spring
prevents any risk of slowing down the gear trains
and thus improves the rate of the movement.
The escapement system comprises a glucidur
balance and an Anachron balance-spring made
by Nivarox (Le Locle) and ensuring a frequency
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of 28,800 vibrations/hour. Thanks to this system,
and for the first time in its history, Universal
Genève earned COSC chronometer certification
for one of its Microtor movements.
The balance-bridge is fitted with a balance-cock
and enables fine adjustment by two screws and
a jewelled Incabloc shock-absorbing system.
Finally a micro-rotor with a diameter of just
12.30mm features a new geometrical shape
entirely different from the design of the brand’s
former Microtor Calibres, and which is also innovative
in relation to the rare competing Calibres.
This rotor is the smallest ever produced for a
Microtor watch, 0.38mm less than the size of the
rotors equipping Calibres UG 66 and UG 71.
The bidirectional rotor, mounted on a double
ball-bearing system, is crafted from sintered tungsten.
The first ball-bearing system meshes with the
reverser pinion and the second with the auxiliary
reverser pinion.
Calibre UG 100 comprises 30 top-quality monocrystalline
jewels, meaning five more than Calibre
UG 72.
The Calibre Microtor UG 100 drives central hour,
minute and seconds hands, as well as the date
shown at 3 o’clock by means of a disc. Measuring
a total 3.80mm thick and only 26.20mm in diameter,
this new movement is the smallest
Microtor Calibre equipped with similar functions
ever produced by Universal Genève.
Microtor UG 100

M icrotor UG 101
2007 Baselworld International Watch and Jewellery
Show: Universal Genève, 1 year after the presentation
of the Microtor UG 100 used in the assembling
of a limited officially chronometer-certified gold
edition of 100 watches (20 in yellow gold and 80
in pink gold), proudly introduce Calibre UG 101
adapted to series production criteria.
Microtor UG 101 features the same technical
characteristics of the Calibre UG 100 including a
chronometer-quality escapement. The circular
Côtes de Genève decorating and finely gilded
engravings on the bridges are reminiscent of the
movements produced by the Manufacture in the
1950s.
Microtor UG 101
Calibre UG 101
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Going-train bridge
Balance-cock
Balance
Micro-rotor
Ball bearings
Mainplate
Barrel-bar
Centre wheel
and pinion
Barrel
Winding-stem
EXPLODED VIEW - CALIBRE UG 100 / UG 101

Bibliography
Swiss Timepiece Makers 1775-1975, Kathleen
H. Pritchard, Published for the National
Association of Watch and Clock Collectors, Inc.
by Editions Antoine Simonin, rue des Saars 99,
CH 2000 Neuchatel, 1997 edition
Menschen – Uhren – Mein Leben, christine
Glauser-Kocher und Hans Kocher, Eigenverlag, 1
Auflage 1997
Universal Genève 100 ans de tradition horlogère,
Italo Bonifacio et Laura Rivolta, Sothis Editrice,
1994 edition
“Liste de brevets déposés auprès du Bureau
Fédéral de la propriété intellectuelle,
Confédération Suisse”
Brevet n°308028, Manufacture des montres
Universal Perret & Berthoud SA, Genève
(Suisse), dépôt 8.11.1952, enregistrement
30.6.1955, publication 1.9.1955
Brevet n° 329805, Manufacture des Montres
Universal Perret Frères, Carouge (Genève),
dépôt 27.5.1955, enregistrement 15.5.1958,
publication 30.6.1958
Brevet n° 330900, Manufacture des Montres
Universal Perret Frères, Carouge (Genève),
dépôt 30.1.1957, enregistrement 30.6.1958,
publication 15.8.1958
Brevet n° 333993, Manufacture des Montres
Universal Perret Frères, Carouge (Genève),
dépôt 29.11.1956, enregistrement 15.11.1958,
publication 31.12.1958
Brevet n° 336004, Manufacture des Montres
Universal Perret Frères, Carouge (Genève),
dépôt 15.7.1957, enregistrement 31.1.1959,
publication 14.3.1959
Brevet n° 336013, Manufacture des Montres
Universal Perret Frères, Carouge (Genève),
dépôt 26.3.1956, enregistrement 31.1.1959,
publication 14.3.1959
Brevet n° 388195, Manufacture des Montres
Universal Perret Frères, Carouge (Genève),
dépôt 2.2.1963, enregistrement 15.2.1965,
publication 15.6.1965
“Journal Suisse d’Horlogerie”
La montre Suisse à remontage automatique,
Calibre Microtor Manufacture des montres
Universal Perret Frères Genève, par B. Humbert,
XIII 2ème série, parution n°4, août 1961
La montre Suisse à remontage automatique,
Calibre Super Slender Buren Watch Co., par B.
Humbert, XIV 2ème série, parution n°5, octobre
1961
La montre automatique la plus mince du monde,
Calibre, publicité Universal et Buren parution
n°11-12, novembre - décembre 1957
Sommes-nous à la veille d’une révolution dans la
construction des montres automatiques ? Par
H.Kocher, directeur technique de Büren Watch
Co A et F. Bandi, technicien chef de la manufacture
des montres Universal à Genève, parution n°
9-10, septembre – octobre 1957

UNIVERSAL GENÈVE S.A.
Geneva - Switzerland
www.universal.ch
Editorial commitee : Vincent Lapaire, Stéphanie Des Arts-Loup,
Christian Müller, Christine Fery-Hammer, Franck Boisseau
Graphic Design : Alexandre De la Riera & Eva Sandoval
Text : Transcribe – A Propos
Printed in Switzerland - April 2007

UNIVERSAL GENEVE SA - SWITZERLAND
www.universal.ch