The Swissonic Prototype

Operating 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.

Face of watch.

 Back of watch

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 On the prototype the trimmers have been replaced by ballast screws to maintain the inertial mass of the fork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.

There are maybe three of these watches still in working order across the world. My thanks go to Barbara Young-Hetzel for deciding that I was worthy enough to receive one. The watch is not for sale so please don't ask.
 
 
 
 

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