Facts About The Accutron Cal 214 Tuning Fork Watches !
Jan 31, 2018 11:34:38 GMT -8
Post by Accutronitis on Jan 31, 2018 11:34:38 GMT -8
Tuning Fork Watches
The first prototype mechanical tuning fork clock, the "pendulum diapason", was manufactured by Louis F. Breguet, grandson of the famous Abraham-Louis Breguet. Louis Breguet filed the patent for this clock in France on October 26, 1866, and a supplement on March 13, 1867. An Irish watchmaker sold this watch in 1961 to the Firm Breguet in Paris, who sold it again a few years later to an unknown collector. Louis Breguet also introduced a clock with a vibrating blade and even mentioned a clock with two tuning forks and another one with two vibrating blades.
Bulova Accutron
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 wristwatch. 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 Raytheon 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 the headquarters in Jackson Heights, New York. The Bulova Accutron is developed by the teamwork 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 his participation in the Normandy Offensive, announces the Bulova Accutroncaliber 214, the first electronic watch in the world. Cased in steel, gold orplatinum, the number of parts had been dramatically reduced to a mere 27of which only 12 were moving parts. By comparison, a self-winding 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 ofNeuch�tel by Ebauches S.A. and by C.E.H. of Neuch�tel.
1973 At this time four million "Bulova Accutrons" have been sold since production started.
The history of the development of the transistor will be dealt with in the next paragraph about watches with balance wheel and transistor.
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 transistorized 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 prolonged 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 backward. 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 million times. To protect the ratchet system, the Accutron may be set only by turning the hands in a forward direction. Another technical hallmark was 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.
The following Bulova calibers can be found:
214 1960. The basic caliber that is used in closed cases and in spaceview (i.e. open) models.Frequency 360 Hz, Power cell 1.30 Volt, Height 5.5 mm and always a backsetting device. Derived calibers:214 H (1962, very small improvements), 214 HN, with calendar (1963), 2140 = 214, 2141 = 214 H, 2142 = 214 HN, 2143 (1970). The numbers 2140,2141 and 2142 are used from 1968 onwards. Four series of the Accutron Astronaut exist:
The Accutron Astronaut with 24-hour bezel is, in addition to the conventional dial and hands, provided with a revolving rim, calibrated into 24 hours and a special Greenwich Mean Time hand which revolves around the dial every 24 hours. This enables the owner to adjust the setting of his timepiece to any two time zones in the world. The movement is the 214 Accutron.
The Astronaut Day/Night. The rotatable outer dial (ring) of the "Accutron Day/Night" is divided into a black half to indicate nighttime hours in another part of the world and a white half to indicate daytime hours (cal 214).
The first prototype mechanical tuning fork clock, the "pendulum diapason", was manufactured by Louis F. Breguet, grandson of the famous Abraham-Louis Breguet. Louis Breguet filed the patent for this clock in France on October 26, 1866, and a supplement on March 13, 1867. An Irish watchmaker sold this watch in 1961 to the Firm Breguet in Paris, who sold it again a few years later to an unknown collector. Louis Breguet also introduced a clock with a vibrating blade and even mentioned a clock with two tuning forks and another one with two vibrating blades.
Bulova Accutron
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 wristwatch. 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 Raytheon 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 the headquarters in Jackson Heights, New York. The Bulova Accutron is developed by the teamwork 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 his participation in the Normandy Offensive, announces the Bulova Accutroncaliber 214, the first electronic watch in the world. Cased in steel, gold orplatinum, the number of parts had been dramatically reduced to a mere 27of which only 12 were moving parts. By comparison, a self-winding 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 ofNeuch�tel by Ebauches S.A. and by C.E.H. of Neuch�tel.
1973 At this time four million "Bulova Accutrons" have been sold since production started.
The history of the development of the transistor will be dealt with in the next paragraph about watches with balance wheel and transistor.
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 transistorized 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 prolonged 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 backward. 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 million times. To protect the ratchet system, the Accutron may be set only by turning the hands in a forward direction. Another technical hallmark was 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.
The following Bulova calibers can be found:
214 1960. The basic caliber that is used in closed cases and in spaceview (i.e. open) models.Frequency 360 Hz, Power cell 1.30 Volt, Height 5.5 mm and always a backsetting device. Derived calibers:214 H (1962, very small improvements), 214 HN, with calendar (1963), 2140 = 214, 2141 = 214 H, 2142 = 214 HN, 2143 (1970). The numbers 2140,2141 and 2142 are used from 1968 onwards. Four series of the Accutron Astronaut exist:
The Accutron Astronaut with 24-hour bezel is, in addition to the conventional dial and hands, provided with a revolving rim, calibrated into 24 hours and a special Greenwich Mean Time hand which revolves around the dial every 24 hours. This enables the owner to adjust the setting of his timepiece to any two time zones in the world. The movement is the 214 Accutron.
The Astronaut Day/Night. The rotatable outer dial (ring) of the "Accutron Day/Night" is divided into a black half to indicate nighttime hours in another part of the world and a white half to indicate daytime hours (cal 214).