A mechanism that is fitted between the gears and the regulating organ in most timepieces. Its function is to control the vibrations of the regulating organ, the balance or the pendulum. The main categories of mechanical escapements generally used in watches and clocks are: 1) Frictional rest escapements, in which the balance is constantly in contact with a part of the escapement; they comprise: a) recoil escapements in which the locking faces are eccentric, causing the escape wheel to recoil sharply during part of the vibration; b) dead-beat escapements, with concentric locking faces, which give no recoil. 2) Detached escapements, in which the balance is detached from the escapement except when locking and receiving the impulse. Clock and watch makers have devised many escapement systems, some of which are still used today.