Mechanical Watch

Overview

A mechanical watch keeps time without electronics, drawing its energy from a coiled mainspring rather than a battery. In the automatic configuration, an oscillating weight winds that spring from the natural motion of the wearer's wrist, so the watch runs continuously as long as it is worn. Stored energy is released in tiny, regulated increments by an escapement governed by a balance wheel, the mechanical analogue of a pendulum.

A self-winding caliber resolves the mainspring's torque into the precise oscillation of the balance through a chain of subassemblies. The Automatic Caliber is the beating heart of the watch, built up on a jewelled mainplate beneath its bridges. It is sealed inside the Case Assembly, whose screw-down crown, caseback, and gasketed sapphire crystal give the watch its water resistance. The time is read off the Dial & Hands assembly, where lumed hands sweep over applied markers and a date wheel shows through an aperture, and the whole watch is worn on the Bracelet.

How it works

Power begins in the mainspring barrel, a coiled flat spring inside a toothed drum that delivers torque to the going (gear) train. The train steps that torque up in speed through the centre, third, and fourth wheels until it reaches the escape wheel.

The escapement meters this energy. A Swiss lever pallet fork alternately locks and releases the escape wheel, and at each release delivers a precise impulse to the balance wheel through its roller jewel. The balance, restored by its hairspring, swings back and forth at a fixed frequency, dividing time into equal beats. An index regulator adjusts the rate by changing the active length of the hairspring.

The automatic winding module carries an oscillating rotor on a ball bearing; reverser wheels rectify its bidirectional motion into one winding direction so the rotor tops up the mainspring continuously. The keyless works switch the crown between winding and hand-setting, while the under-dial motion works divide the motion 12:1 to drive the hour hand.