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The Encyclopedia of Horology

Frictional rest escapement

Verge (crown-wheel) escapement

Verified

Two pallets on a vertical verge staff alternately engage the teeth of a horizontally mounted crown wheel, giving impulse and recoil on every vibration.

Schematic arrangement

How it is laid out

Crown wheelVerge staff & balance

Outline schematic only, drawn to show the characteristic arrangement of wheel, locking member and oscillator. It is not a dimensioned working drawing and should not be used for setting up or repairing a movement.

Advantages

  • Tolerant of crude manufacture
  • Simple to make and repair

Drawbacks

  • High friction
  • Rate varies with mainspring torque
  • Poor isochronism

Attribution and period

c. 1300 in clocks; adapted to watches by the sixteenth century

Horological firsts are frequently contested. Where an invention is attributed to a named maker, that attribution is recorded as such rather than treated as settled fact.

Photographs

Verge Escapement Labelled
Verge Escapement Labelled — Henry Evers, Public domain. Wikimedia Commons file page
Verge escapement Giovanni di Dondi
Verge escapement Giovanni di Dondi — Giovanni de Dondi, Public domain. Wikimedia Commons file page
1845 Verge Escapement pocket watch
1845 Verge Escapement pocket watch — Rosser1954, CC BY-SA 4.0. Wikimedia Commons file page

Photographs are matched automatically from freely licensed Wikimedia Commons material. Each caption states the actual subject of the image and credits its author; where a close match for this escapement does not exist, a related mechanism may be shown instead.