| 摘要 |
The balance-spring is formed by a first assembly, comprising the coils ( 3 ) and the outer curve ( 2 ), made in a first material such as Elinvar having an elastic torque that is insensitive or almost insensitive to elongation, temperature and magnetic field variations, and by a second assembly secured to the first assembly, comprising in particular the inner curve ( 4 ) made of a second material essentially selected for its mechanical properties and for the shapeability of said inner curve ( 4 ) along the most favourable contour for concentric expansion of the balance-spring, such as a Grossmann curve ( 14 ), said second assembly also being able to comprise a collet ( 5 ).
|
