Big Ben, tower clock, famous for its accuracy and for its massive bell. properly speaking , the name refers to only the good hour bell, which weighs 15.1 tons (13.7 metric tons), but it's commonly related to the entire tower at the northern end of the homes of Parliament, within the London borough of Westminster. The tower itself was formally referred to as St. Stephen’s Tower until 2012, when it had been renamed Elizabeth Tower on the occasion of Elizabeth II’s jubilee , celebrating 60 years on British throne. The hands of the clock are 9 and 14 feet (2.7 and 4.3 metres) long, respectively, and therefore the tower rises about 320 feet (97.5 metres). Originally in coordination with the Royal Greenwich Observatory, the chimes of massive Ben are broadcast—with a couple of interruptions—since 1924 as a daily signal by British Broadcasting Corporation.
The clock was designed by Edmund Beckett Denison (later Sir Edmund Beckett and Lord Grimthorpe) in association with Sir George Airy (then astronomer royal) and therefore the clockmaker Edward Dent. Denison’s principal contribution was a completely unique gravity escapement that imparted unprecedented accuracy to the clock. during a clock an gear is allowed to rotate through the pitch of 1 tooth for every double swing of the pendulum and to transmit an impulse to the pendulum to stay it swinging. a perfect escapement would transmit the impulse without interfering with the free swing, and therefore the impulse should be as uniform as possible. The double three-legged gravity escapement designed by Denison for giant Ben achieves the second of those but not the primary . Big Ben is wound 3 times every week , and therefore the winding takes over an hour. Big Ben is accurate to within two seconds per week. The pendulum is adjusted by adding pennies made before the decimalization of the United Kingdom’s currency in 1971 to the load . Each penny causes Big Ben to realize 0.4 second per day.
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