Flat spiral spring for use in e.g. timepiece, has oblong opening provided to receive regulating element whose position is movable in opening, where radius of curvature of opening is equal to that of outer turn of spring

摘要

The spring (10) has an inner end associated with a collet (12), and an outer end associated with a balance-spring stud (14). An outer turn of the spring comprises a portion divided into two strips (16). The strips define an oblong opening (18) in between, where the opening has radius of curvature equal to that of the outer turn of the spring. The opening is provided to receive a regulating element (20) whose position is movable in the opening, where the spring is made of diamond and monocrystalline silicon, and is covered with an oxide layer and a diamond layer. An independent claim is also included for a flat spiral spring and a regulating element assembly comprising a mobile support on which a regulating element is fixed.