Component record · Keyless work
Yoke
VerifiedA forked lever within the keyless works that engages a groove on the stem and shifts the clutch wheel between its winding and setting positions.
What it does
Translates the axial pull or push of the crown and stem into lateral movement of the clutch wheel, switching the keyless works between winding and hand-setting modes.
How it works
A groove machined into the stem accepts the yoke's forked end, so that when the stem is pulled outward the yoke is forced to pivot about its own pivot point.
The yoke's other end bears against the clutch wheel, pushing it axially along the stem into the setting-train mesh position as the crown is pulled, and allowing it to return to the winding position when the crown is pushed back in.
A separate setting lever and its spring hold the yoke firmly in one of its two stable positions, giving the crown a distinct, positive click as it is pulled or pushed.
Evolution
A standard component of nearly all keyless works since their introduction, with only minor variation in exact geometry between calibres.
Known variations
- Simple pivoted yoke
- Combined yoke-and-setting-lever assemblies in some compact keyless designs
Identification for collectors
- Visible as a forked lever bridging the stem groove and the clutch wheel when the dial-side keyless works are exposed
Common failure modes
- Worn fork tips allowing the stem to move without properly shifting the clutch wheel
- Broken or weakened setting-lever spring causing the crown position to feel loose or to slip back unintentionally
Related photographs
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No confidently matched photograph of this subject has been found yet. These photographs show a closely related record, and are not examples of the type described on this page.
Sources & references
- de Carle, D., Practical Watch Repairing
Where sources disagree, the disagreement is stated rather than resolved silently.