Hairspring for movement of timepiece, has spiral spring including inner coil having piton biasing device with free end arranged to attach to piton in plane of spiral spring, where biasing device includes extension part

摘要

The hairspring (7) has a spiral spring (11) including an inner coil having a sleeve (10) arranged to be mounted on a shaft (2), and another spiral spring (13) connected to an outer coil of the former spiral spring by a curve elevation device (15). An inner coil of the latter spiral spring includes a piton biasing device (17) with a free end (6) arranged to attach to a piton in a plane of the latter spiral spring. The biasing device includes an extension part (12) extending from the inner coil of the latter spiral spring. An independent claim is also included for a movement.