AUTHENTIC VINTAGE BULOVA ACCUTRON 218 RAILROAD GENTS WRISTWATCH

BRAND/JENAMA: AUTHENTIC VINTAGE BULOVA ACCUTRON 218 RAILROAD GENTS WRISTWATCH

MADE IN/BUATAN: SWISS

CIRCA/TAHUN: 1976

MODEL: RAILROAD

CRYSTAL/CERMIN: ACRYLIC

MOVEMENT/ENJIN: BULOVA ACCUTRON 218 TURNING FORK MOVEMENT

DIAL COLOR: SILVER TONES

FUNCTION/FUNGSI: QUICK SET DATE AT 3:00

HANDS/JARUM: SILVER TONE/ KEPERAKAN

MARKERS/TANDA WAKTU: RAISED SILVER TONE STICKS MARKERS

BEZEL: -

CASING : SOLID STAINLESS STEEL

LUGS: 18mm

MEASUREMENT/UKURAN: 37mm DIAMETER INCLUDING CROWN and 42mm LUG TO LUG

DITANDA/ENGARVED BACK CASING: BULOVA~STAINLESS STEEL CASE~N6 (1976 - PLEASE CHECK BULOVA DATING )

CROWN: SIGNED ACCUTRON SS CROWN (BRASING)

STRAP/TALI: GENUINE NEW BLACK LEATHER STRAP

SIZE STRAP/SAIZ TALI: 8.5"

WORKING CONDITION, HUMMING AND KEEPING TIME ACCURATELY, DISCONTINUED MODEL & VERY HARD TO FIND

PRICE/HARGA: RM700.00 (NEGOTIABLE/BOLEH DIRUNDING)

Brief Information on Bulova Accutron Turning Fork

The low frequency of the balance wheel made it impossible to improve the accuracy of the present mechanical watches. Therefore the Bulova Watch Company Switzerland, knowing that the American army was in need of a better time base for their instruments, asked the Swiss engineer Max Hetzel in 1952 to look into the possibility of the application of a higher frequency in a watch.
Max Hetzel was born in Basle in 1921, graduated in 1946 at the Zurich Federal Polytechnic School as an electronic engineer, worked on TV and Communications and joined the Bulova Watch Company of Bienne, Switzerland, in 1948.
This outstanding engineer was the first one to use an electronic device, a transistor in a wrist watch. Thus, Max Hetzel developed the first watch in the world that truly deserved the qualification 'electronic': the world-famous 'Bulova Accutron'.

1953	Max Hetzel receives the first useful transistors, the 'CK 722', from Raython USA and produces his first working model by hand. The length of the tuning fork was five centimeters. The patent application is filed in Switzerland on June 19th 1953 under no. 312290.
1954	The ATO electronic pendulum clock is shown at the CIC in Paris, the first clock in the world with a transistor and without electrical contacts. In June, the first useful batteries suitable for watches, invented by Mallory, become available. In November, the first prototype wristwatch is made to function.
1955	Eight watch-sized models are produced in Bienne. In Switzerland many doubted whether 'The Accutron' would become successful.
1956	The president of the Bulova Watch Co. in New York, Arde Bulova, and his engineers become enthusiastic about the tuning fork system.
1959	Max Hetzel goes to New York with his family and becomes Chief Physicist at the headquarters in Jackson Heigts, New York. The Bulova Accutron is developed by team work of two scientists: Max Hetzel and William O. Bennett. The start of the production-engineering phase takes off.
1960	On October 10th, the new president of the Bulova Watch Co., Omar N. Bradley, ex-chief of staff of General D. Eisenhower and known for hisparticipation in the Normandy Offensive, announces the Bulova Accutron caliber 214, the first electronic watch in the world. Cased in steel, gold or platinum, the number of parts had been dramatically reduced to a mere 27 of which only 12 were moving parts. By comparison, a selfwinding watch at that time contained about 136 parts, 26 of them moving. The sale of the Accutron starts on October 25th.
1964	The 'Bulova Accutron' is chosen to be buried for a time period of 5000 years on the grounds of the New York World Fair in order to save it for future generations as an example of one of the 44 most innovative objects to be invented during the last two and a half decades.
1964-1970	In different trips into space with the 'Explorer' and the 'Apollo', the 'Bulova Accutron' is used by astronauts with full satisfaction.
1966	The first tuning fork wrist watches are registered at the Observatory of Neuchtel by Ebauches S.A. and by C.E.H. of Neuchtel.
1973	At this time four million 'Bulova Accutrons' have been sold since production started.

Description of the Accutron.

The 'Bulova Accutron' has a frequency of 360 oscillations per second (360 Hz). The vibration of the tuning fork is controlled by a transistorised circuit in the following way:

When the left magnet on the tuning fork moves to the right, the phase-sensing coil generates an induction voltage on the base of the transistor. The transistor 'switches on', becomes a conductor instead of a resistor and the electrical current is able to start flowing through the right circuit. The drive-coil becomes a magnet and gives an impulse to the permanent magnet. The movement of the permanent magnet in the driving-coil also causes an induction voltage opposing the power cell voltage. The result is a very small electric current and a prolongued battery life.
The problem of turning the linear motion of the fork into a circular motion of the hands is solved in the following way: the index jewel is connected to the fork and pushes the ratchet wheel one tooth forward, the pawl jewel is fixed to the watch frame and prevents the ratchet wheel from revolving backwards. The ratchet wheel was an outstanding technical achievement: 2.4 mm in diameter, 0.04 mm thick and 300 teeth, each 1/100 mm high. In one year it revolves 38 milion times. To protect the ratchet system, the Accutron may be set only by turning the hands in a forward direction.
Another technical hallmark were the coils: the driving coil has 8,000 turns made of wire with a diameter of 0.015 mm and an incredible length of about 90 meters.