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The Encyclopedia of Horology

Complication · Precision

Constant Force Escapement

Partially verified

An escapement that delivers a consistent amount of energy to the balance regardless of mainspring tension.

Definition

An escapement that delivers a consistent amount of energy to the balance regardless of mainspring tension.

Historical origin

A historic quest in horology, from remontoires to modern silicon blade solutions.

How it works

A small intermediate spring (remontoire) or a flexible blade stores a tiny amount of energy and releases it in discrete pulses.

This isolates the escapement from the varying torque of the mainspring.

Pocket watch context

Found in high-grade chronometers and some experimental English lever watches.

Wristwatch context

Revived in modern watches like the Girard-Perregaux Constant Escapement.

Identification

  • A small spring or blade visible snapping back and forth near the escapement

Servicing notes

Requires advanced understanding of escapement dynamics.

General guidance only. Complicated mechanisms should be assessed and serviced by a qualified watchmaker or clockmaker specialist, not adjusted at home.

Diagram

balance wheel with timing screwsflat or overcoil hairspringregulator index
Schematic: balance, hairspring and regulator. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

  1. de Carle, D., Watch and Clock Encyclopedia
  2. Britten, F. J., Old Clocks and Watches and Their Makers
  3. Horological Journal (British Horological Institute), technical articles

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