Self-compensating balance spring for mechanical spiral balance-wheel oscillator of e.g. timepiece, has silicon bar with exterior surface, and material in form of cover, where cover partially covers exterior surface

摘要

#CMT# #/CMT# The spring (1) has a silicon bar (2) with an exterior surface (3), where the silicon bar has a young's modulus thermal coefficient. A material partially compensates the thermal coefficient, where the material is Invar (RTM: nickel iron alloy), Elinvar (RTM:nickel steel alloy), or Kovar (RTM: nickel-cobalt ferrous alloy), silicon oxide. The material is in a form of a cover (4). The cover is made of metal or alloy, where the cover partially covers the exterior surface. #CMT#USE : #/CMT# Self-compensating balance spring for a mechanical spiral balance-wheel oscillator of a timepiece or precision instrument (all claimed). #CMT#ADVANTAGE : #/CMT# The configuration of the spring enables reducing the sensibility to thermal variations and magnetic field. The spring is easy and comfortable to use. The spring can be manufactured in an inexpensive manner. The cover partially covers the exterior surface, thus increasing the esthetic appearance. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a longitudinal sectional view of a segment of a balance spring. 1 : Self-compensating balance spring 2 : Silicon bar 3 : Exterior surface 4 : Cover 8 : Doped oxide cover.