Tuning-fork watch

In a tuning-fork watch the timekeeping oscillator is a small metal fork kept vibrating by electromagnets and a transistor circuit, its vibration converted into rotary motion to drive the hands. Max Hetzel's US patent 2,900,786, "Timepiece arrangement", assigned to Bulova Watch Company, Inc., filed 31 May 1956 and granted 25 August 1959, describes "an arrangement of an electric timepiece incorporating a vibrator for driving the timepiece mechanism", built around a "tuning-fork type vibrator having a base and a pair of oscillatable tines".

The dates and figures usually quoted for the Accutron are the company's own. An Accutron press release states that "65 years ago, on October 25th, Accutron changed the industry with the original Tuning Fork movement", calls it the "first electronic wristwatch, achieving unheard-of accuracy within 2 seconds per day", and says that "the 360 Hz vibration required precision tolerances that demanded completely new micro-engineering processes". All three figures are the brand's own statements about itself.

Use of the movement beyond wristwatches is on the public museum record. The Smithsonian National Air and Space Museum's record for a Skylab timer made by Bulova Watch Company (inventory A19761052000) states that "timers like this were used by astronauts to time experiments and other events during the Skylab missions (1973-1974)", and that it uses "the 'Accutron' movement developed by Bulova for wristwatches". The National Museum of American History holds a military Accutron wristwatch of about 1970, catalogue 1993.0254.09.

What this Codex does not do: extend that record to other programmes. The Air and Space Museum record names Skylab; the wider claim on Bulova's own pages that the timing device "was adopted for the Apollo program" was not verified against a museum or NASA record.