| 摘要 |
The invention relates to a ferrule, a balance wheel having the ferrule and a timekeeper, and the ferrule is to prevent the formation of cracks in a main body portion when a balance staff is externally press-fitted. The ferrule (50) is used to fix the inner end (43) of a spring (40) to the balance staff (30). The ferrule (50) comprises a main body portion (51) including an opening (53) coaxially externally sleeved on the balance staff (30) and a support portion ( 55) which is formed to protrude toward an outer side in a radial direction of the main body portion (51) and which supports the spring (40), a sealing surface (57) at which the inner end (43) of the spring (40) is welded and which is formed on a side of the support portion (55) in the radial direction, and a concave portion (60) which is formed on at least one end surface (56a) of two end surfaces the support portion (55) in an axial direction of the main body portion (51). |
