Securing device for the outer end of the hair-spring of a timepiece
AssigneeFabrique d'Horlogerie de Fontainemelon S.A.
InventorRene Widmer
Life of this patent
Estimating the term…
Abstract
A securing device which permits the outer end of the hair-spring in a timepiece to be fastened either by gluing or pinning it in place. A U-shaped arm extends radially of the axis of the balance wheel and provides a pair of ears, one for gluing the hair-spring and the other for pinning it. The manufacturer of the watch can thus use the ear for gluing the outer end of the hair-spring, as this method has advantages for production purposes. When the hair-spring is replaced, the watch-repairman can use the other ear for pinning the outer end of the hair-spring without deforming the hair-spring, thereby obtaining the advantages of this method for repair purposes.
Claims2
In a timepiece having a balance wheel, a hair-spring and a support therefor, a securing device for the outer end of said hair-spring comprising
- a U-shaped arm extending radially of the axis of said balance wheel and having a pair of thin-walled ears disposed parallel to each other and to said axis, said ears being disposed at a predetermined angle to the radial plane through the middle of said arm,
- one of said ears being provided with a first opening for receiving and fixing the outer end of said hair-spring by gluing it therein,
- the other of said ears being provided with a second opening for receiving the end of said hair-spring and having a securing pin for fixing it is said second opening when it is not glued in said first opening,
- said other ear being disposed on a radial plane through the axis of said balance wheel such that the plane of said second opening is perpendicular to the tangent to said hair-spring at the point where it is fixed by said pin.
Dependencies are inferred from the claim text.