Spring detent escapement In mechanical watches, the spring detent escapement transforms the energy from the unwinding of a coiled spring (the power source) into countable impulses. In 1775, John Arnold successfully redesigned this mechanism. Around 1783, Thomas Wright used this design to manufacture the earliest known pocket chronometer (coming soon to Clocktime), which was created during the contest between Thomas Earnshaw and Arnold to invent a reliable spring detent escapement.
