The Luxury Watch Blog

Bulova is a New York based corporation making watches and clocks.

Bulova was founded and incorporated as the J. Bulova Company in 1875 by Joseph Bulova (1851-1936), an immigrant from Bohemia. It was reincorporated under the name Bulova Watch Company in 1923, and became part of the Loews Corporation in 1979..

Bulova established its operations in Woodside, New York and Flushing, New York, where it made innovations in watchmaking, and developed a number of watchmaking tools. Its horological innovations included the Accutron watch which used resonating tuning forks as a means of regulating the time keeping function. In July 1941 Bulova paid $9 for the first television commercial, a 10-second spot on WNBT during a baseball game between the Brooklyn Dodgers and Philadelphia Phillies.

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Luxury Swiss watch company Jaeger-LeCoultre—in partnership with actor and activist Leonardo DiCaprio—has created its “Time to Care” program, to benefit the Leonardo DiCaprio Fund at the California Community Foundation.

The fund-raising focal point of the initiative will be the sale of two timepieces in the fall of 2008. Both will be the first of a limited series of watches that feature technology never used before, Jaeger-LeCoultre said in a statement. All proceeds will go to the Leonardo DiCaprio Fund at the CCF in order to further its work with environmental programs worldwide. The watches will be presented exclusively at the new Jaeger-LeCoultre Boutiques in Boca Raton and Beverly Hills, scheduled to open summer and fall of this year, respectively.

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How it works

To accomplish this, the watch contains a semicircular ‘rotor’, an eccentric weight that turns on a pivot, within the watch case. The normal movements of the user’s arm and wrist cause the rotor to pivot back-and-forth on its staff, which is attached to a ratcheted winding mechanism. The motion of the wearer’s arm is thereby translated into the circular motion of the rotor that through a series of reverser and reducing gears, eventually winds the mainspring. Modern self-winding mechanisms have two ratchets and wind the mainspring during both clockwise and counterclockwise rotor motions.

The fully-wound mainspring in a typical watch can store enough energy reserve for roughly two days, allowing automatics to keep running through the night while off the wrist. Usually automatic watches can also be wound manually by turning the crown, so the watch can be kept running when not worn, and in case the wearer’s wrist motions are not sufficient to keep it wound automatically.[1]

Preventing overwinding

A problem that had to be solved with self-winding mechanisms is that they continued working even after the mainspring was fully wound up, putting excessive tension on the mainspring. This caused a problem called ‘knocking’ or ‘banking’. The excessive drive force applied to the watch movement gear train made the balance wheel rotate with too much amplitude, that is too far in each direction, causing the impulse pin to hit the back of the pallet fork horns. This made the watch run fast, and could break the impulse pin. To prevent this, a slipping clutch device is used on the mainspring so it cannot be overwound.

The slipping spring or ‘bridle’

The ’slipping mainspring’ device was patented by Adrien Philippe, founder of Patek Philippe on June 16, 1863, long before self-winding watches. It was originally invented to allow simultaneous winding of two mainspring barrels. In an ordinary watch mainspring barrel, the outer end of the spiral mainspring is attached to the inside of the barrel. In the slipping barrel, the mainspring is attached to a circular steel expansion spring, often called the ‘bridle’, which presses against the inside wall of the barrel, which has serrations or notches to hold it.

As long as the mainspring is less than fully wound, the bridle holds the mainspring by friction to the barrel wall, allowing the mainspring to be wound. When the mainspring reaches full wind, it’s force is stronger than the bridle spring, and further winding pulls the bridle loose from the notches and it simply slides along the wall, preventing the mainspring from being wound further. The bridle must grip the barrel wall with just the right force to allow the mainspring to wind fully but not overwind. If it grips too loosely, the mainspring will begin to slip before it is fully wound, a defect known as ‘mainspring creep’ which results in a shortened reserve power time.

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