Wristwatches
The first wristwatches hit the market at the end of the 19th century.
As an example you can see a watch from Audemars Frères. (after 1885, nickel silver case, 17-stone full anchor movement, compensation unrest with Breguet hairspring and swan neck fine adjustment, four stones set in chatons, large onion crown, white enamel dial with Arabic numerals and a small second dial, small black pointer, black Breguet pointer).
The similarity to a pocket watch is unmistakable - but they weren't a big seller. But this should change - through war or women?
The first to need a wristwatch were the aviators, who needed the time for navigation and flight duration. A pocket watch made in the cockpit, e.g. with the fighter pilots of the First World War no sense.
Pocket watch movements were initially used for this purpose. Because of the crown, the 12 points toward the hand. Since the time is awkward to read, wristwatch movements were developed.
Example: Small pocket watch movement installed as a wristwatch. Silver case with metal inner lid, lined back with empty monogram mirror, 15 jewels full lever movement, Swiss made, brass metal dial with applied lined Arabic numerals and minute dots, two Breguet hands, small second dial with brass hand.
The wristwatch also became more popular with the ladies of the house.
Example: Golden ladies' pocket watch reworked into a wristwatch, round, with Arabic numbers and decorative pointers, back cover with floral decorations, cover that can be opened, 1st quarter of the 20th century.
With the tensioning brackets with telescopic strap, jewelry watches and women's pocket watches could be worn like wristwatches. They had the advantage that the 12 on the dial was parallel to the wrist, making it easier to read the time.
In the 40s and 50s of the 20th century, the wristwatch prevailed over the pocket watch.
Example: watch from the company 'Les Fils d'Armand Nicolet, Manufacture des Montres Telda S.à.r.L.' made of Tramelan in the Bernese Jura from approx. 1950, dial with Arabic numerals, 17 jewels, black leather strap, steel case. Day, date and month display.
The watchmaking industry in the French and Swiss Jura has been declared a World Heritage Site by UNESCO.
Max Hetzel (* 1921 in Basel)
In 1951, the Basel physicist Max Hetzel joined the Bulova Watch Company (New York / Biel) in order to, among other things. to develop a tuning fork watch. The first prototype was available in 1954, and the wristwatch was ready for series production in 1960. Hetzel initially worked in the USA for the Gemini and Apollo programs.
The demonstration movement of the electronic tuning fork clock from Bulova is built into a square brass part. A transistor circuit causes the tuning fork to vibrate (360 Hz) via the electromagnetism of two coils. An indexing pawl on the tuning fork engages a gearwheel with 360 teeth and thus transmits the power to the gear train. This sets the hands in motion. The name Accutron is made up of the English words accuracy and electronic.
"If we want to send astronauts to the moon and they should come back safe and sound, we need very precise clocks," was the unanimous opinion of NASA. A spring balance oscillates up to 5 times a second, so the tuning fork watch from BULOVA came at just the right time, the tuning forks vibrate at 360 Hz (later 440 Hz). These clocks were built into the Gemini capsules and the lunar lander. The astronauts themselves had Omega watches on their wrists - an Omega Speedmaster - because they did not know how the magnetic fields in space influence the accuracy of the Accutron.
The quartz watch (1970s)
A quartz watch is a watch whose clock is an oscillating crystal with a standard frequency of 32768 Hz. Halving this frequency 15 times results in a seconds normal that is transmitted electronically or mechanically to a display.
Since electronics are built in, the Hewlett-Packard company developed a clock with a pocket calculator. The computer clock HP-01 was launched on June 1, 1977.
The radio controlled clock
The radio clock is usually a quartz clock, the time of which is synchronized at least once a day with the time signal broadcast by the long-wave transmitter DCF77 in Mainflingen near Frankfurt.
The radio clock was registered for a patent in 1967 by Wolfgang Hilberg from the Telefunken company. The first radio-controlled wristwatches were manufactured by the Junghans company in 1990.
This inexpensive watch from Junghans, brand Eurochron, has a movement made in Japan with the number 615.45-5700 and a CR1220 battery. It has no jewels.
