Single-body double spiral and method for manufacturing same

摘要

The spiral (21) has a collet (27) formed by patterns. One of the patterns is projected from a hairspring (23) and formed in a silicon based layer. The hairspring is coaxially mounted on the collet. Another pattern is extended into another silicon based layer so as to be coaxial with another hairspring (25) for forming the monoblock double spiral in silicon based material. The hairspring (23) made of silicon based material is oxidized. An internal spire of one of the hairsprings is provided with a Grossmann curve. An independent claim is also included for a method for fabricating a double spiral.