Glossary/Detent Escapement
Detent Escapement
A detent Escapement is an accurate detached escapement in which the balance wheel is impulsed in one direction only. During its swing, the balance wheel moves aside a detent which releases one tooth of the escape wheel. This tooth gives the balance wheel a push in the direction in which it is going and is then locked. On the return swing of the balance a so-called 'passing-spring' prevents the escape wheel from being unlocked.
As the beat of Marine Chronometers is usually half a second and the escape wheel moves at every other beat, the seconds hand shows dead beat seconds. Invented for use on ships at sea by Thomas Mudge, Thomas Earnshaw, and Julien Le Roy in the early eighteenth century.
Also called the 'chronometer escapement'.