Oscillator for use in tourbillon cage of watch movement, has felloe, counterweights and hair spring arranged such that rotation of counterweights diametrically opposite to each other from marks of scale corresponds to variation of inertia

摘要

The oscillator has a balance spring including a hub (14), and a felloe (18) integrated with arms (16) of a plate (12). The spring has counterweights (22) i.e. cylindrical pellets, rotatably mounted on the felloe around a rotation axis. A rod (10) carries the spring by the hub. A hair spring (24) is fixed on the rod. The felloe, the counterweights and the hair spring are arranged such that rotation of the counterweights diametrically opposite to each other from marks of a scale (18d) of the felloe corresponds to variation of inertia equal to n divided by 86400, where n is an integer.