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The Encyclopedia of Horology

Component record · Power

Click

Verified

A small, spring-loaded pawl that engages the ratchet wheel's teeth to enforce one-directional winding.

What it does

Prevents the mainspring barrel arbor (and hence the wound spring) from turning backwards, holding wound tension in the spring between winding strokes.

How it works

The click's nose sits in a ratchet-wheel tooth root, held there by the click spring's pressure. When the arbor is turned in the winding direction, the click's shaped nose is cammed up and over each successive tooth, clicking audibly as it drops into the next root.

If the arbor tries to rotate the opposite way — as it constantly tends to under mainspring tension — the click's nose meets the steep face of a tooth and jams solid against the click's pivot, locking the ratchet wheel and preserving the wound state of the spring.

A weak, broken or displaced click spring is one of the most common simple watch faults, since it lets the mainspring unwind through the winding mechanism rather than through the train, and the watch will not hold a wind.

Evolution

Essentially unchanged in principle for centuries; refinements are limited to materials and precision of the tooth/pawl geometry.

Known variations

  • Barrel click (as described)
  • Setting/keyless work clicks performing analogous locking roles elsewhere in the winding system

Identification for collectors

  • A watch that will not wind, or winds with no resistance and no audible clicking, usually has a broken or dislodged click or click spring

Common failure modes

  • Broken click spring
  • Worn click nose or ratchet teeth
  • Click spring detached from its post

Photographs

Nineteenth century miracles, or, Spirits and their work in every country of the earth - a complete historical compendium of the great movement known as "modern spiritualism" (1884) (14596522817)
Nineteenth century miracles, or, Spirits and their work in every country of the earth - a complete historical compendium of the great movement known as "modern spiritualism" (1884) (14596522817) — Internet Archive Book Images, No restrictions. 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. de Carle, D., Practical Watch Repairing

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