1960 · Tuning-Fork Electronic Watch · Work 838 of 1,871
A wristwatch on the green felt of a watchmaker's bench in New York in winter, a round stainless steel case thirty-five millimetres across on a black leather strap, its dial open to the movement, in the upper half two tiny orange-red coils side by side with the silvery tines of a tuning fork between them, below them turquoise-green and silver plates and a small wheel, slim silver hands, a hand in a white coat sleeve lifting the watch toward the ear of a head soft at the edge of the frame, another hand holding a watchmaker's loupe, an open parts tray, tweezers, a work lamp with a green shade from the upper left.
What it was used for
The Bulova Accutron was a wristwatch whose timekeeping element was not a balance wheel but an electrically driven tuning fork running at 360 Hz. A transistor kept the fork in oscillation; its movement was transferred to a 300-tooth index wheel that drove the train. The 214 movement measured 28.7 mm across and 5.5 mm high. The watch was designed for 2 seconds a day or 1 minute a month. It was shown at a press conference on 25 October 1960; over 400,000 were made through 1968, and the 214 movement is listed as produced from 1960 to 1969.
What was new
What marked it out was replacing the mechanical regulator with a vibrating piece of metal at a fixed frequency: 360 Hz instead of the beat of a balance wheel, audible as a hum rather than a tick. Max Hetzel, who joined Bulova in 1950, argued in a 1952 report that the transistor was the decisive component and in 1953 obtained a Raytheon CK 722, a low-current transistor; Swiss patent no. 312290 was registered on 19 June 1953. 7 years lay between the patent registration and series production from November 1960. The transistor was at first a germanium PNP type, later replaced by a silicon NPN type.
What the sources leave open: 360 Hz, 300 teeth, dimensions, the press conference of 25 October 1960, over 400,000 made through 1968 and the 1960-1969 production years from Grail Watch Reference; Hetzel, the patent number, the CK 722 and the accuracy figure from the Clinique Horlogère, which contradicts itself on the year of introduction (to the public in 1961, elsewhere in 1960) and gives 27.80 rather than 28.7 mm diameter. No museum record was reachable; neither source describes the pawl mechanism.