Control mechanism for watch part

A control mechanism for timepiece of the type comprising a frame (10) furnished with two parallel faces defining a reference plane, one of which is intended to support a dial and the other is opposite the back, and, secured to this frame:

• a control rod (12) furnished with an annular groove (14) having a width l, an external diameter D and an internal diameter d, mounted so as to move in translation on the frame (10) along a first axis (AA′) included in said plane, and
• a retaining plate (20) mounted, on the back side, on the frame (10) parallel to said plane and comprising a locking piece (22) mounted so as to rotate about a second axis (BB′) perpendicular to the reference plane and arranged such that it is capable of occupying:
• a first position, called the locking position, in which the translation movement of said rod (12) is limited by the engagement of the locking piece (22) in the groove (14), and
• a second position, called the unlocking position, in which said locking piece (22) is no longer engaged in the groove (14) thus allowing the rod (12) to be pushed in on the frame (10) or pulled out,
• characterized in that said locking piece (22) comprises:
• a first part (26) of general cylindrical form, engaged in the retaining plate (20) in order to allow its rotation on the plate;
• a second part (34) disposed on the side opposite to the rod (12) and arranged to allow said locking piece (22) to rotate, and
• a third part (38), disposed on the side of the rod (12), intended to interact with it and comprising, for this purpose, two wings (40) inscribed in a dummy cylinder of the same axis as the second axis (BB′) and of slightly smaller diameter than the width l of the groove (14), said wings being arranged such that, in the locking position, the wings (40) are at least partly inscribed in the space between the external diameter D of the groove (14) and the internal diameter d and, in the unlocking position, the wings (40) take on the contour of the external diameter D.