① Pendulum: composed of a pendulum, a pendulum rod, a hanging pendulum device, and a periodic adjustment device. Used in fixed clocks. When the pendulum deviates from the plumb line (equilibrium position) at any angle under external force and is released, under the action of gravity, the pendulum will move back and forth around the fulcrum. The vibration process is the alternating conversion of kinetic energy and potential energy of a pendulum.

② Twisted pendulum: mainly composed of a pendulum disc and suspension wire. The lower end of the suspension wire is fixed on the swing plate, and the upper end is fixed on a fixed fulcrum. The cross-section of the suspension wire can be rectangular or circular. The torsion pendulum often forms an escapement speed control system with a backward escapement mechanism or a forked tile escapement mechanism. Twisted pendulum has a long vibration period (several seconds to tens of seconds), and is often used in fixed clocks that save energy and have a longer travel time.

③ Swivel and hairspring vibration system: The inner and outer ends of the hairspring are respectively fixed on the swing shaft and swing clamp plate. When the pendulum wheel deviates from its equilibrium position due to external forces and begins to swing, the hairspring is twisted to generate potential energy, commonly known as restoring torque. This torque drives the pendulum to move towards its equilibrium position.