Without doubt, the most unique and strangest tuning fork watch ever made!

In 1973, Omega introduced the Calibre 1220 and 1230 "Megasonic F720 Hz" watches to the Basle Fair. The calibre was developed by Max Hetzel, the inventor of the Bulova Accutron.

There are several amazing features about this calibre:

1. It has an asymmetric tuning fork that resonates at 720 Hz instead of the more normal 300 Hz.

2. On one of the tines of the tuning fork is the Omega Micromotor. This motor consists of an oil filled sealed box with a transparent cover. In this box is a wheel mounted on four rubies. When the fork vibrates, this wheel bounces off two opposite ruby springs; finally there are two index arms opposite each other to prevent the wheel moving back in the reverse direction. The bouncing off of the ruby springs plus the indexing induces a rotational motion in the wheel.

3. The Micromotor is a sealed unit with no visible means to drive the rest of the movement! In addition, there is no physical connection between the vibrating tuning fork and the movement. This calibre uses a series of magnetic gears to drive the movement; the first few gears in the train have no teeth normally associated with gears but instead have magnets that pass very close to each other, thus implusing the next gears. This wonderful design is shown in the diagrams below.

In the next photgraph, you can clearly see the Micromotor attached to one tine of the asymmetrical tuning fork. The ruler scale shows millimeters. In servicing this calibre, you have to take great care to keep the magnetic gears away from the strong magnets of the tuning fork: should they come into contact with each other, the much smaller magnetic gears would instantly be destroyed.

The complete movement. Note the copper screw plate screw near the Micromotor.