A lever escapement is a mechanism used in watches and portable clocks to release the power of the mainspring in regular, measured steps, controlled by an oscillating balance wheel and hairspring. A pivoted lever with two pallets locks and releases the teeth of the escape wheel, and at each swing gives the balance a brief impulse while otherwise leaving it free to oscillate.
The detached lever escapement was invented by the English clockmaker Thomas Mudge in the middle of the eighteenth century, but it was slow to be adopted. Because the balance is detached from the train for most of its swing, the lever offers far better timekeeping than the earlier verge and cylinder escapements and copes well with movement and knocks. By the late nineteenth century it was standard in good-quality pocket watches and was widely used in carriage clocks and other portable timepieces, often mounted on a separate platform above the movement. Collectors of carriage clocks look for a lever platform in good order, as it is generally preferred to the cheaper cylinder type. Wear to pivots, jewels and pallets should be checked by a specialist, as servicing is delicate work.
