1965: Max Hetzel develops the Swissonic prototype watch in an attempt to circumvent his prior patents.
Once the Accutron had been launched on the market, Hetzel returned to Switzerland where he was recruited in 1963 by the Centre for Electronic Horology (CEH) in Neuchâtel. There he developed the Swissonic, a variant of the tuning-fork watch with the oscillator configured as a horseshoe around the movement. The initial series was scheduled to go into production in a pilot plant managed by Hetzel in Gals near the town of Marin in Canton Neuchâtel. But the project collapsed when the Swissonic design turned out to infringe the Bulova patent.
The Swissonic PrototypeOperating Characteristics
Frequency 480 Hz
Accuracy +/- 1.5 sec/day
Clickwheel No of Teeth 200 teeth
Clickwheel diameter 1.5mm
The Swissonic Prototype is a development from Max Hetzel. He sought to develop a Swiss tuning fork timepiece , without infringing the Accutron patent. The prototype was ready in 1965 afterwards Hetzel began with preparations for production. The timepiece was never produced as it none the less infringed Bulova Accutron patent.
It's design is similar to patent 1,060,702.
FACE OF WATCH
WATCH MOVEMENT
Note how the prototype tuning fork above differs from the 'pre-production' fork as shown below.
The prototype has no trimming devices. On the pre-production fork these are eccentric circlips which can be rotated to change the frequency of the tuning fork by a few milli-percent and regulate the time keeping of the watch. On the prototype the trimmers have been replaced by ballast screws to maintain the inertial mass of the fork
The prototype fork seems to be monolithic whilst the pre-production model appears to have been fabricated from three separate pieces although it is difficult to see how this would be possible whilst maintaining the required degree of accuracy and uniformity from fork to fork.
It is believed there are three or fewer of these watches still in working order across the world.
Much of the information on this page was taken from Sean Connor's Accutron page which is no longer active. You can find an archive of it HERE.
In 1969 Hetzel joined Omega, who hired him to circumvent his own patent of 1953. To this end he developed a most original oscillating motor. It consists of an asymmetrical turning fork vibrating at 720 Hz and became the Omega Megasonic F720Hz which was produced in limited quantities and sold to the public.
Here is the only known video of a running Swissonic Prototype W tuning fork watch.
Swissonic Prototype W Tuning Fork watch on Youtube
