A power transmission body of a timepiece in which a fixed portion between an arbor and a power transmission member is hardly damaged is provided without increasing the number of components. A transmission wheel (one example of power transmission body) includes a gear and a pinion (one example of arbor). A hole formed in a center portion of the gear includes a regular octagon with a rotation center as a center. An insertion portion formed in the pinion includes a gear-like portion including a tooth bottom and a tooth tip. The hole includes eight portions that are positioned in a circumference direction about the rotation center and contact the insertion portion. The hole includes a portion that is positioned in front of the eight portions in a clockwise direction (specific rotation direction) about the rotation center and has a distance from the rotation center longer than a distance from the rotation center to each of the eight portions.

A power transmission body of a timepiece in which a fixed portion between an arbor and a power transmission member is hardly damaged is provided without increasing the number of components. A transmission wheel (one example of power transmission body) includes a gear and a pinion (one example of arbor). A hole formed in a center portion of the gear includes a regular octagon with a rotation center as a center. An insertion portion formed in the pinion includes a gear-like portion including a tooth bottom and a tooth tip. The hole includes eight portions that are positioned in a circumference direction about the rotation center and contact the insertion portion. The hole includes a portion that is positioned in front of the eight portions in a clockwise direction (specific rotation direction) about the rotation center and has a distance from the rotation center longer than a distance from the rotation center to each of the eight portions.

A timepiece movement includes second, minute, and hour hand wheels with second, minute, and hour hand arbors; a 24-hour hand wheel with a 24-hour hand arbor; and a first to third guides that guide an arbor to which a hand attaches. The minute, hour, and 24-hour hand arbors have tubular configurations and are disposed coaxially to the second hand arbor. The minute hand arbor has a diameter greater than the second hand arbor, the hour hand arbor has a diameter greater than the minute hand arbor, and the 24-hour hand arbor has a diameter greater than the hour hand arbor. The first guide is between the second hand arbor and the minute hand arbor, the second guide is between the minute hand arbor and the hour hand arbor, and the third guide is between the hour hand arbor and the 24-hour hand arbor.

A timepiece movement includes second, minute, and hour hand wheels with second, minute, and hour hand arbors; a 24-hour hand wheel with a 24-hour hand arbor; and a first to third guides that guide an arbor to which a hand attaches. The minute, hour, and 24-hour hand arbors have tubular configurations and are disposed coaxially to the second hand arbor. The minute hand arbor has a diameter greater than the second hand arbor, the hour hand arbor has a diameter greater than the minute hand arbor, and the 24-hour hand arbor has a diameter greater than the hour hand arbor. The first guide is between the second hand arbor and the minute hand arbor, the second guide is between the minute hand arbor and the hour hand arbor, and the third guide is between the hour hand arbor and the 24-hour hand arbor.

The mechanical timepiece movement with power reserve indication comprises at least one barrel system connected to a winding wheel of a differential gear and an unwinding wheel of the differential gear. An intermediate wheel of the differential gear is connected to a cam wheel set to drive it in rotation via a reducing stage. A rack, which acts on a power reserve indicator, is in contact with the cam wheel set. When the power reserve is at zero, a locking part of the rack comes into contact with a locking member to lock the movement at an unwinding output of the barrel system or in contact with the unwinding wheel of the differential gear.

The mechanical timepiece movement with power reserve indication comprises at least one barrel system connected to a winding wheel of a differential gear and an unwinding wheel of the differential gear. An intermediate wheel of the differential gear is connected to a cam wheel set to drive it in rotation via a reducing stage. A rack, which acts on a power reserve indicator, is in contact with the cam wheel set. When the power reserve is at zero, a locking part of the rack comes into contact with a locking member to lock the movement at an unwinding output of the barrel system or in contact with the unwinding wheel of the differential gear.

Method for producing a surface of revolution of a clock or watch component comprising a step of machining, with a femtosecond laser beam, a first surface of the clock or watch component so as to obtain a second surface, in particular so as to obtain a second surface whose roughness Ra is less than 100 nm, or less than 70 nm, and then a tribofinishing step applied to the second surface so as to obtain the surface of revolution.

An escape wheel & pinion serving as a mechanical component includes an axle and an escape wheel serving as a rotary member having a holder for holding the axle. The axle has a recessed portion into which the holder is fitted. A tapered portion inclined in an axial direction of the axle is disposed in a portion where the recessed portion is in contact with the holder.

An escape wheel & pinion serving as a mechanical component includes an axle and an escape wheel serving as a rotary member having a holder for holding the axle. The axle has a recessed portion into which the holder is fitted. A tapered portion inclined in an axial direction of the axle is disposed in a portion where the recessed portion is in contact with the holder.

A timepiece shaft (1), especially a balance shaft (1), comprising a first functional portion (2a; 2b) including at least one part (221a; 221b) of a pivot-shank (22a; 22b) and/or at least one part (211a; 211b) of a pivot (21a; 21b), the first functional portion being made of ceramic and a first outer diameter (D1) of the first functional portion being less than 0.5 mm, or less than 0.4 mm, or less than 0.2 mm, or less than 0.1 mm.