In 1960 the Bulova Accutron was introduced. It revolutionized the wristwatch world. It was the first electronic ( that is transistorized) wristwatch. It used a totally different timesource namely a tuningfork. Untill then all wristwatches had a balance as a time source.It's accuracy was unsurpassed: Bulova garantueed as first company in the world an accuracy of no less then one minute a month, while most wristwatches were inaccurate like one minute a day. It was invented by Mr. Max Hetzel. As a hobby i do small repairs (especially timing an Accutron to run as accurate as better then 1 minute/month) and sell Accutrons. I have completed the school of fine mechanics in Leiden (LIS), the same school as Mr.van der Klaauw and Mr. van der Gang have completed. Feel free to use any of my diagrams but please refer to this site if you do. Thank you.

This movie shows the functioning of the indexsystem. The indexsystem converts the lineair movement of the tuningfork into a rotation that drives the hands. Note that the blue theethed wheel (indexwheel) is 2,4 mm in diameter and has 360 (!) teeth. The tuningfork fibrates with a frequency of 360 times per second. The pink block (indexfinger) is attached to the tuningfork. the purple block (pawlfinger) acts only to avoid the indexwheel from rotating clockwise. Note that the amplitude of the tuningfork maybe anything between more then 1 tooth and less then 2 teeth. This means that between these limits battery voltage may vary.
Also, the accuracy of an Accutron depends mainly on the accuracy of the frequency of the tuningfork. An accuracy of better then 60 seconds a month requires an accuracy of about 1/50.000 Hz! How about that for finemechanics:D