PIVOTING DEVICE FOR AN ARBOR INSIDE A TIMEPIECE

摘要

#CMT# #/CMT# The device has bearings for receiving pivots, where each bearing includes a plastic pivoting structure (25), where the device is made of metal or alloy. Each pivot (12) has a convex rounded portion (13) forming an extension of a cylindrical portion and decreasing in size in a direction of a pivot end. The structure has an opening (16) e.g. circular opening, comprising a trapezoidal/inverted-triangle profile whose inclined inner wall forms a bearing surface. The portion (13) is supported against the wall such that a shaft is axially maintained between the walls of openings of the structures. #CMT# : #/CMT# An independent claim is also included for a method for assembling a shaft pivoting device. #CMT#USE : #/CMT# Device for pivoting a balance shaft in a timepiece e.g. watch. #CMT#ADVANTAGE : #/CMT# The rounded portion is supported against the inner wall such that the shaft is axially maintained between the inclined inner walls, thus reducing variation of friction force torque between different orientations of the timepiece. The difference of oscillation amplitude of the balance between the different orientations is therefore reduced. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a partial schematic sectional view of a pivoting structure of a shaft pivoting device. 12 : Pivot 13 : Convex rounded portion 15 : Axial stop 16 : Opening 21 : Radial guiding unit 25 : Pivoting structure 27 : Cylindrical cavity.