Spring roller for timepiece balance shaft - has alternating equiangularly spaced concave and convex surfaces

摘要

The spring roller is used for fixing the spiral drive spring to the balance shaft of a timepiece balance mechanism. It is formed from a hollow cylindrical blank, which is deformed to provide alternating equi-angularly spaced concave and convex peripheral surfaces. The concave surfaces (17, 18, 19) resiliently act against the outer surface of the balance shaft (1) and one of the convex surfaces (6, 7, 8) is used for attachment of the inner end (9) of the spiral spring. Pref. the roller has three or four concave surfaces (17, 18, 19) and three or four convex surfaces (6, 7, 8).