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The Encyclopedia of Horology

France (origin); England (Tyrer's patented refinement) · Origin c. 1720s–1750s (contested); Thomas Tyrer patented an English form in 1782

Duplex Escapement

Partially verified

Valued for accuracy at reasonable cost, the duplex escapement was widely used in mid-tier English watches and extensively in watches made for the Chinese export market before the lever escapement's cost fell enough to displace it.

The duplex escapement uses an escape wheel with two sets of teeth — long teeth for locking and short teeth for impulse — acting on a single roller on the balance staff, giving a largely detached action without the lever's added parts.

Tyrer's 1782 English patent is the most concretely documented milestone in the escapement's development, though the underlying French-attributed concept predates it by several decades according to horological historians.

How to verify this yourself

Tyrer's 1782 patent should be sought in The National Archives (Kew) historical patent enrolment series under his name; earlier French-attributed origins rest on horological-history literature rather than a surviving patent and should be cited as attribution, not as a documented filing.

Manufacturers known to have used it

  • English watchmakers, late 18th–19th centuries
  • Swiss export houses supplying the China trade

Photographs

Duplex Escapement
Duplex Escapement — Harry Leonard Nelthropp, Public domain. Wikimedia Commons file page
Duplexhemmung
Duplexhemmung — F. J. Britten, Public domain. 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. Britten, F. J., Old Clocks and Watches and Their Makers
  2. The National Archives, Kew — patent enrolment index (existence of Tyrer's filing noted, number not independently verified here)

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