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The Encyclopedia of Horology

Switzerland · Cottier's world-time mechanism developed from 1931 onward, with a series of Swiss patent filings across the 1930s–1940s (including filings recorded in 1930, 1948 and 1949 covering movable-dial and world-time systems)

Cottier World Time Mechanism

Partially verified

Cottier's world-time display became, and remains, the standard architecture for the world-time watch complication across the Swiss high-horology trade, and Patek Philippe's Cottier-designed world-time watches and clocks are among the most sought-after complications from the period.

Louis Cottier, an independent Geneva-area watchmaker, developed a mechanism displaying the time in a set of world cities simultaneously via a rotating 24-hour ring and city disc, refined from an earlier movable-dial concept into the world-time watches and clocks he supplied to Patek Philippe, Vacheron Constantin and other Swiss houses from the 1930s onward.

Cottier filed multiple Swiss patents across the 1930s and 1940s covering successive refinements of the movable-dial and world-time display system; the exact scope and number of each individual filing require direct verification against the Swiss patent register rather than assuming a single foundational patent covers the whole mechanism.

How to verify this yourself

Individual Cottier Swiss patent filings and grants should be confirmed against the Swiss Federal Institute of Intellectual Property's historical register by inventor name; auction-house archival lots (which have sold original Cottier patent documents and drawings) are a useful corroborating source but not a substitute for the primary register.

Manufacturers known to have used it

  • Patek Philippe
  • Vacheron Constantin
  • Longines (early period)

Sources & references

  1. Beyer Museum, Zurich, published history of Louis Cottier and the World Time Clock
  2. Antiquorum, archival lot descriptions of original Cottier patent documents (used to corroborate the existence and approximate dates of filings, not as a primary patent-office record)

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