Horological movement comprising a flat hairspring

摘要

The spring (10) has windings that are made of a single band extending from an inside curve (11) to an outside curve (14). The inside curve is extended by a self blocking washer (17) that allows the spring to be fixed on axis (9) of a balance-wheel. A rectangular section having a non-uniform thickness (e) is presented between an attachment to a center and an attachment to outside. An independent claim is also included for a method of manufacturing a hair-spring from a board in an amorphous or crystalline material.