Verge escapement A verge escapement is a type of escapement consisting of a crown wheel and a verge. The two pallets projecting from the verge alternately engage with and disengage from teeth on either side of the crown wheel. The crown wheel rotates in a constant direction, while the verge rotates first one way until one pallet engages on one side of the crown wheel, before then being pushed by the crown-wheel tooth in the opposite direction until it disengages; then, the second pallet is engaged, reversing the direction of the movement once more. The alternate movement of the verge, controlled either by a balance wheel or a pendulum, controls the speed of the crown wheel and hence the entire train. The verge escapement was widely used from the Middle Ages with early balance-wheel and also with a short pendulum, particularly in portable spring clocks. It has a large recoil and tolerates the clock operating from a non-level table.
