Ratchet
角穴車／カクアナグルマ
棘轮
Ratchet
Rochet
Glossary
Thematic
Technic, Transmission
A saw-toothed wheel.
The ratchet wheel in a watch is a toothed wheel that is fixed by a square hole to the barrel arbor. A click (pawl) prevents the ratchet wheel from turning in the unwinding direction.
In a striking mechanism, the hour-ratchet or hour-rack is a toothed sector that lifts the hammer to strike the hours.