Patent ID: 9594350
Date: 2017-03-14
CPC Classifications: G04B

Claim:
1. A timepiece balance spring made of micromachinable material comprising a plurality of stages, each forming a spiral wound spring, all parallel to each other and arranged to be assembled to each other at the respective inner ends thereof in a common axial collet or on the same balance staff, wherein each said stage includes, at the respective outer end thereof, specific means of attachment to a balance spring stud which are independent of those of said other stages, said means of attachment comprising means for position adjustment with respect to a balance spring stud which are also independent of those of said other stages, said means of attachment and said means for position adjustment together forming built-in isochronism correction means for said balance spring, wherein said position adjustment means of a said stage include a plurality of discrete position adjustment positions comprising housings each arranged to retain a stud.