Galilei's experiment in 1612
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electric clocks

 A history of the evolution of electric clocks

G. The first free pendulum

The idea of a free pendulum as Galileo Galilei (1564-1642) had in mind shortly before his death fascinated many inventors but no one yet had succeeded. Only a free pendulum, a pendulum having no work to do of any kind, can - in theory - be used as a true timekeeper.

Robert James Rudd
It appears that Rudd was the first to solve this problem in 1898.
In the illustration seen here (patent no.19337) the lower end of a free Rudd pendulum is moving to the left just before receiving an impulse.
When the electro-magnet is energized, triggered by a secondary clock, the armature will turn a cam releasing a lever holding a roller. Rotated by a weight, this lever will give the pendulum its impulse. When the lever has given its impulse to the pendulum and has nearly completed its semi-revolution it breaks a contact.
Breaking this contact forms the synchronizing signal determined by the free pendulum only.                                      

Although Rudd had now solved the problem of the free pendulum, he lacked to make his invention well known. He does not appear to have realized that his invention contributed anything to the science of accurate time measurements.

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H. Shortt's free pendulum




Electricity & Magnetism
Electricity & Horology
   A.Electrostatic clocks
   B.The first inventors
   C.Independency of battery
   D.Reliability of contact making
   F.Count-wheel and impulse
   G.The first free pendulum
   H.Shortt's free pendulum
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