A mechanical clock keeps accurate time through the following key components and principles:
- Escapement mechanism: This is the core component for timekeeping. It typically consists of a balance wheel (in watches) or a pendulum (in larger clocks), along with an escape wheel and pallets. The balance wheel or pendulum oscillates at a specific frequency. For example, a pendulum's oscillation period is determined by its length and the force of gravity. As it swings back and forth, it interacts with the escape wheel through the pallets. With each oscillation, the escape wheel is allowed to advance by a fixed amount, which regulates the flow of energy from the power source to the gear train, thus controlling the overall speed of the clock.
- Gear train: Composed of multiple gears with different numbers of teeth, the gear train transmits the power from the power source (such as a spring or weight) to the hands of the clock. The specific ratios of the gears are designed to convert the relatively fast rotation of the power source into the slow and precise movement of the hour, minute, and second hands. This ensures that the hands move at the correct rates to indicate the passage of time accurately. For example, a series of gears may be used to reduce the speed of the mainspring - driven shaft so that the minute hand makes one full rotation in 60 minutes and the hour hand moves one - twelfth of a rotation in the same time.
- Regulating devices: Some mechanical clocks have additional regulating mechanisms to fine - tune the timekeeping. For example, a balance - wheel clock may have a adjustable hairspring. The tension and length of the hairspring can be adjusted to change the frequency of the balance wheel's oscillations, thereby correcting any inaccuracies in the clock's timekeeping. In pendulum clocks, the length of the pendulum can often be adjusted to change its period of oscillation and keep the clock running accurately.