Breguet overcoil balance spring made of micro-machinable material

摘要

The invention relates to a Breguet overcoil balance spring (1) that includes a hairspring (3) mounted in a single part, made of micro-machinable material, and coaxially with a collet (5). According to the invention, the balance spring has a terminal curve (7) made of micro-machinable material and an elevation device (9) made of micro-machinable material between the outer coil (15) of the hairspring and the terminal curve to improve the concentric development of the balance spring. The invention also relates to the method of manufacturing the balance spring. The invention concerns the field of timepiece making.