Hand-winding

Hand-winding is the transfer of energy into the mainspring by turning the crown. The crown sits on a stem, and the stem drives the keyless works. A patent assigned to Ebauches Bettlach SA, "Winding and setting mechanism for watches" (US 3,827,235, filed 18 June 1973), describes a drive pinion "rigidly connected with the stem" and a "sliding crown wheel" "cooperating with the ratchet wheel for the winding of the drive spring". Pushed in, the stem winds the spring; pulled out, the same pinion meshes with the setting wheel and the hands move instead.

The arrangement is old. Christopher Kuenzel's US patent 739,089, "Stem winding and setting watch", published 15 September 1903, describes a stem whose "outward movement" "insures the forcing of the clutch out of winding engagement with the barrel and the setting-pinion into setting engagement with the hand-setting train of gearing," one crown doing two jobs, which is still how a hand-wound watch behaves.

What winding achieves is stored torque. Grand Seiko's technical page states that "a wound-up mainspring exerts force to turn gears at a set speed as it unwinds". Hand-winding is not confined to watches without a rotor: Montres Breguet's 2022 automatic-winding patent describes a movement wound both by an oscillating mass and, still, through the winding stem.

"Hand-winding" is trade vocabulary rather than a defined technical term. The primary documents cited here call the assembly a "winding and setting mechanism", and no standards body, metrology institute or museum record read for this entry defines the phrase itself.