StemwindingMechanismus

The stemwinding mechanism is the part of mechanical clocks and watches that converts the turning of the winding stem and crown into winding motion for the mainspring. Its primary purpose is to store energy by tightening the mainspring so that the gear train can drive the timekeeping elements.

Key components typically include the winding stem and crown, the winding pinion, the clutch or sliding pinion, the crown wheel, the ratchet wheel, and the mainspring barrel. A pawl and click provide a one-way clutch that prevents the mainspring from unwinding unintentionally. When the crown is turned, the winding pinion engages the ratchet wheel, which turns the mainspring barrel and winds the mainspring. In most designs, the clutch allows the pinion to disengage during overwind or when the crown is pulled out for setting, protecting the mechanism.

Operation is straightforward: rotating the crown transmits motion through the stem and gears to wind the mainspring. The resulting stored energy is released gradually through the gear train to power the escapement and timekeeping. In many watches, the crown can also be pulled to a setting position, which disengages the winding mechanism and engages the setting train for hands and calendar adjustment.

Variations exist in precision, protection against overwinding, and the presence of additional features such as slipping springs or different clutches. The stemwinding mechanism is commonly found in manual-winding watches and some clocks, and it sits alongside automatic winding systems in modern timepieces. Regular lubrication and protection from dirt are essential for reliable operation.