Skip to content
The Encyclopedia of Horology

Watch family · Movement

Automatic (Self-Winding) Watches

Partially verified

Watches wound by the natural motion of the wearer's arm via an oscillating weight (rotor) or, in earlier designs, a pivoting bumper weight, rather than solely by hand.

Movement & mechanism

  • Oscillating rotor geared to wind the mainspring via a reduction train and ratchet/pawl system
  • Earlier 'bumper' automatics use a weight swinging between two spring-loaded stops instead of a full rotor
  • Slipping bridle or similar device in the barrel to prevent overwinding

Identification

  • Weighted rotor visible through a display back
  • Case back marked 'automatic' or 'self-winding'
  • Winding crown may still hand-wind and set in most designs

Terminology

  • Rotor — the swinging weight winding the mainspring
  • Bumper — an earlier semi-circular oscillating weight design
  • Slipping bridle — a mainspring anchor point allowing it to slip once fully wound

Known variations

  • Bumper automatic
  • Full-rotor automatic
  • Micro-rotor automatic

Pocket-watch ancestry

Self-winding mechanisms were experimented with in pocket watches from the late eighteenth century (associated with Abraham-Louis Perrelet and later Abraham-Louis Breguet's 'perpétuelle' watches), using a pivoting weight; wristwatch automatics revived this principle because wrist motion, unlike a pocketed watch, provides continuous movement well suited to winding a rotor.

Collecting notes

Early bumper automatics and pioneering full-rotor calibres are collected for their historical significance in the development of the self-winding watch.

Photographs

Vintage LeGant QS, Sold by Montgomery Ward, Automatic (Self-Winding) Wrist Watch, Made in Japan (11756267656)
Vintage LeGant QS, Sold by Montgomery Ward, Automatic (Self-Winding) Wrist Watch, Made in Japan (11756267656) — Joe Haupt from USA, CC BY-SA 2.0. Wikimedia Commons file page
Self-winding wristwatch (transparent backside)
Self-winding wristwatch (transparent backside) — Petar Milošević, CC BY-SA 4.0. Wikimedia Commons file page
Cadisen C8173 automatic wristwatch
Cadisen C8173 automatic wristwatch — Francis Flinch, CC0. Wikimedia Commons file page

Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.

Sources & references

  1. Daniels, G., Watchmaking
  2. Priority claims among early 18th-century self-winding pocket watch makers remain debated.

Where sources disagree, the disagreement is stated rather than resolved silently.