In 1966 the swiss-american owner Gsell wanted to retire and engineered the acquisition of Buren by the Hamilton Watch Company USA. Hamilton transferred its production 1969 to Buren, doubling its capacity to about half a million pieces per year. The Swiss company was bought by the American Hamilton watch company the same year.

The automatic movements were further developed, together with Breitling, Heuer-Leonidas and Dubois-Depraz, to build the world‘s first automatic chronograph the CHRONOMATIC® Cal. 11, where the crown seldom to use in an automatic watch was set at the left of the dial, the two chronograph push-pieces at the right side.

CH1375667

STATEMENT OF INVENTION N°1375667

DECEMBER 17, 1966, 5¾ p.m.

Class 83a Buren Watch Company s/A. (Switzerland).

The subject matter of the invention is a lever movement for a wristwatch with an escapement controlled by a balance wheel with a higher frequency of vibrations, which is driven by a spring barrel via a wheel train consisting of a large base wheel, a small base wheel, a seconds wheel mounted in the s center of the movement, and an escapement wheel consists.

In contrast to the usual balances, which, depending on the caliber, vibrate 18,000 to 22,000 vibrations per hour, a balance wheel with a higher number of vibrations is to be understood as meaning a balance wheel that performs at least 30,000 vibrations per hour.

As is well known, such a balance wheel has the advantage that its oscillations are considerably less disturbed by arm movements than with ordinary balance wheels. A balance with a higher number of oscillations has the effect on the rate of the watch that practically no more fluctuations can be detected, so that a watch equipped with such a balance runs just as accurately as a watch with an electronically controlled rate regulator.

The members of the CHRONOMATIC® group realised the importance of secrecy in their work. With four partners in the group, and a host of other companies that would come to be involved in the production of cases, dials and other components, there were many people involved in the day-to-day operation of the project. Confidentiality was of utmost importance, as the CHRONOMATIC® group raced against unknown opponents to produce the first automatic chronograph.

Throughout the term of the project, employees of the participating companies were prohibited from uttering the phrase, "automatic chronograph". With that, this unusual partnership became "Project 99". In September 1967 and in collaboration with Dubois Dépraz, we filed a patent for Calibre 11. The combination of a micro-rotor movement and a chronograph module was more than successful. After the success of the first tests in 1968, Breitling produced a first pre-series of CHRONOMATIC®.

CH1113467

STATEMENT OF INVENTION N°1113467

AUGUST 8, 1967, 5¾ p.m.

Class 83a Buren Watch Company s/A. (Switzerland).

The object of the present invention is a wristwatch with mainspring. His goal is to create such a watch, comprising both an automatic winding mechanism with a moving mass for this spring, and a chronograph mechanism.

Many mechanisms have already been combined in a watch of the type indicated above, so as to create a so-called “complicated” watch. We have thus imagined automatic winding mechanisms that it is possible to mount afterwards on different watch movements, for example clock-watch movements.

Also known are watches with automatic winding by moving mass, further comprising a minute counter. However, the latter do not allow the second hand to be stopped in order to allow an accurate reading before bringing the counter mechanism back to zero.

In the watch according to the invention, the various organs of the chronograph mechanism are mounted on the movement of the watch, above all the organs of the automatic winding mechanism, and the space swept by the mobile mass of the latter mechanism, seen in plan, is lower than the surface of the movement.

CH98168

STATEMENT OF INVENTION N°98168

APRIL 15, 1967, 18 p.m. 

Class 83a Buren Watch Company s/A. (Switzerland).

Watch movements equipped with two barrels each containing a spring are already known. One of the barrels is connected to the train of the movement while the other activates, for example, the ringing of an alarm clock.

In some cases, however, the force of the two springs housed in the barrels is used to actuate the gear train in order to achieve long running time watch movements. The barrels then rotate more slowly than is the case in usual movements and the same is true of the first moving part of the multiplier gear train which is driven simultaneously by the two barrels.

The presence of two barrels makes it possible to obtain a significant driving force. In some cases, the first moving part of the train is placed upstream of the high-average moving part and the gear train comprises five moving parts. In other cases, the minute indicator organ is driven indirectly and the gear train comprises only four mobiles.

The prototypes of the first automatic CHRONOMATIC® were presented to the public on 3 March 1969 at a world press conference. The event was held at the Hotel Intercontinental in Geneva, as well as at the Pan Am Palace in New York and Tokyo, Hong Kong and Beirut, more than a month before the Basel Fair.

The notoriety of the brands involved is a major asset and the presentation of the CHRONOMATIC® is much more talked about than the Zenith models. The members of the quartet showed the public their dozens of pre-production CHRONOMATIC® samples, watches equipped with the Calibre 11 movement, with several models from Heuer, Breitling and Hamilton, in a variety of different cases and colours.

In the summer of 1969, the CHRONOMATIC® group achieved mass production of their models, which then became available to the public in the world's major retail markets. In conclusion, the synergie formed by Buren, Dubois-Depraz, Breitling, Hamilton & Heuer is considered the creator of the world's first automatic chronograph with its CHRONOMATIC® Calibre 11 model. This was used by the four brands to develop models that remain anchored in the history of watchmaking

such as the Heuer Autavia, the Breitling CHRONOMATIC® and the Heuer Monaco. The Kelek brand used these calibres and the initials JRGK, for Jean-Raoul Gorgerat Kelek, are engraved on the chronograph bridge. Other brands such as Bulova and Elgin, Zodiac and Stowa, also used the CHRONOMATIC®. Hamilton transferred its production 1969 to Büren, doubling its capacity to about half a million pieces per year.

CH535470

STATEMENT OF INVENTION N°535470

APRIL 10, 1970, 6p.m.

Class 83a Buren Watch Company s/A. (Switzerland).

The main patent No. 508905 relates to a watch movement with mainsprings comprising an oscillator with a balance and a spiral spring and two barrels each containing a mainspring, the teeth of these barrels being engaged with the same mobile constituting the first mobile a multiplier gear train actuating the oscillator, the latter being arranged to oscillate at a frequency greater than 30,000 vph (vibrations per hour) and said mobile of the multiplier gear train being the high-speed mobile average.

This main patent describes a mechanical watch whose balance wheel oscillates at a frequency greater than 30,000 vib/h and in which the problems linked to the increase in frequency are solved by using two barrels each rotating at the usual speed of rotation and attacking the center pinion simultaneously.

This arrangement has the following advantages: possibility of making a watch with a high frequency, 36,000 vph for example, a sufficient power reserve for it to be equipped with an automatic winding device, and a balance whose moment of inertia is sufficient for, under the expected operating conditions, improved rate precision to be obtained compared to current watches at 18,000 or 21,600 vph.

According to the aforementioned main patent, it was possible to give the mainsprings housed in the barrels significant torques without the reactions of the bearings on the pivots of the wheel sets of the gear train and especially on the shaft of the wheel set of large average not reaching values exaggerated.

Like most movements, the Calibre 11 has been optimised several times over its lifetime. As early as 1969, a barrel spring providing less torque is used. The date jump mechanism is adapted. The sliding pinion is changed and made in steel. In 1971, a variant running at 21,600 vibrations per hour and named Calibre 12 is introduced. It becomes the main product of the calibre family. It uses a stronger barrel spring.

The gear train and balance wheel are adapted. The chronograph hammer is modified to improve shock-resistance. The Calibre 13 is developed to integrate a small seconds indication in the periphery of the hour counter but will never be commercialised. In 1972, the Calibre 14 adds a GMT function and the Calibre 15 adds a small seconds to the Calibre 12, positioned at 10 o’clock, replacing the elapsed hours sub-counter.

CH124671

STATEMENT OF INVENTION N°124671

JANUARY 28, 1971, 6p.m.

Class G04b Buren Watch Company s/A. (Switzerland).

Watches are already known in which the time indicator device is arranged so that the hour hand can be moved by a manual command by a whole number of hours without affecting the position of the hour hand. minutes in order to enable users of these watches, when moving between regions belonging to different time zones, to set them to local time without having to modify the adjustment of the minute hand.

These known indicating devices generally comprise a coupling connecting two mobiles which together constitute the hour wheel and which have a certain number of determined relative orientations in which the two mobiles are integral in rotation with one another.

This solidarisation is only effective if the torque transmitted from one mobile to another is low. Under the action of a greater torque, the wheel bearing the hour hand is disengaged from the actual hour wheel and can therefore pass from one orientation to the next. 11 is clear that to avoid disturbing the movement of the watch when the time is being corrected, this coupling must disengage under the effect of a relatively low torque. On the other hand, for construction reasons, it is advantageous for this coupling to have dimensions that are as small as possible.