autowinder

An autowinder is a device that automatically winds a mechanical watch. It is also known as an automatic or self-winding mechanism. The primary function of an autowinder is to harness the natural motion of the wearer's wrist to keep the mainspring of the watch wound. This eliminates the need for manual winding, which is required for traditional mechanical watches.

The core component of an autowinder is a rotor, typically a semi-circular or full-circle weight that is free to rotate. As the wearer moves their arm, the rotor swings or spins. This rotational movement is then transferred through a series of gears to a winding mechanism, which tightens the mainspring. The mainspring stores the energy that powers the watch's movement.

There are two main types of autowinding systems: the bumper system and the rotor system. The bumper system, common in earlier automatic watches, features a weighted arm that swings back and forth, hitting buffers. The more prevalent rotor system uses a centrally mounted rotor that spins freely in a full circle. When the mainspring reaches its full tension, a clutch mechanism disengages the winding system to prevent overwinding. This allows the watch to continue running as long as it is worn regularly. The introduction of the autowinder was a significant innovation in watchmaking, offering convenience and continuous operation for mechanical timepieces.