Watch hairspring and method for making same
1 Assignment
0 Petitions
Accused Products
Abstract
The invention relates mainly to a hairspring intended to equip the balance wheel of a mechanical timepiece. It is in the form of a spiraled rod (10) cut from an {001} single-crystal silicon plate. Its structure and its dimensions are calculated so as to minimize the thermal drift of the hairspring/balance-wheel assembly by means of the first and second thermal coefficients of its spring constant.
-
Citations
22 Claims
-
1-11. -11. (canceled)
-
12. A hairspring intended to equip the balance wheel of a mechanical timepiece and in the form of a spiraled rod (10) cut from an {001 } single-crystal silicon plate having a first thermal coefficient (C1) and a second thermal coefficient (C2) of its spring constant C, the turns of said hairspring having a width w and a thickness t, characterized in that said rod comprises a silicon core (12) and an external layer (14) of thickness ξ
- formed around the silicon core and made of a material having a first thermal coefficient of the Young'"'"'s modulus of opposite sign to that of the silicon.
- View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
Specification