Collet for mounting balance spring of mechanical watch movement, has continuous metal band with inner contour delimiting recesses and forming collet, where band has variable width in plane perpendicular to balancing staff

摘要

The collet has a continuous metal band (10) with an inner contour (11) delimiting recesses (11a-11c) and including three contact points (1, 3, 5) contacting with a balance staff (2) of angular angles (alpha1, alpha3 and alpha5). The angle (alpha3) is symmetric with respect to a reference axis (XX') and oriented towards a junction point (4) located on an outer contour (12) of band and at an end of an arm (14) at a distance (R) from a centre (O) of staff higher than other junction point (6, 8) of outer contour.. The band forming the collet has a variable width in a plane perpendicular to staff.