The Balance





The escapement, Escape Wheel and Pallet Lever, together with the Balance System is the real heart of the movement. The Escape Wheel and the Pallet Lever together perform two different but equally important tasks: to control the rate by which the Mainspring unwinds and to repeatedly give the Balance Wheel its needed impulse. The Balance Wheel and the Hairspring constitutes a mechanical oscillator with a stable frequency.


  The figure shows the top side of main plate without any components. At the top right are the Balance Bridge and the Balance. At the bottom right are the Pallet Lever Cock and the Pallet Lever.



This figure shows the Pallet Lever put into its position and fixed by the Pallet Lever Cock. The Balance is also at its correct position on the main plate. 



Here the Balance Bridge is in place. The end stone of the balance shock-protection system in not mounted.



This figure shows the end stone and the balance shock-protection mechanism.  One great improvement in watch design was when the shock-protection system was introduced. The idea is to prohibit breakage of the balance arbor pivots by allowing the jewel bearing and an end-stone - also called cap-jewel - to move controlled by a spring. The spring holding the shock-protection together is of different shapes in different watch manufacturer's designs.



  Here the Escape Wheel is in place completing the heart of the movement.



The regulator, a part of the balance system, is the fine tuning system to make the balance oscillate at the correct frequency. It's like finding the right pitch on a violin string by gliding a finger up and down the string.  The violin player does this to regulate the length of the string and hence get right frequency.  In the watch movement you control the effective length of the hairspring in a similar way by moving the regulator index arm, bottom left in the figure. N.B that the movement is in operation in the figure, the Escape Wheel has moved some steps during the exposure of the photo.