Every mechanical watch has an escapement, the part that transfers the stored energy of the mainspring to the oscillating balance wheel. It does this in tiny, discrete pulses, locking the wheel train between each one. Each pulse is a tick. The escapement is the single component that separates a mechanical watch from a decorative curio: without it, the mainspring unwinds in seconds. With it, the mainspring unwinds over 40 to 80 hours in exactly 28,800 regular pulses per hour.
The Swiss lever escapement, invented by English watchmaker Thomas Mudge around 1755, is the architecture used in virtually every mechanical wristwatch made today. A lever with two pallets alternately locks and releases the escape wheel; the escape wheel in turn delivers an impulse to the balance wheel, which then returns via the hairspring to release the next lock. The system is self-starting, shock-resistant, and mass-producible. Mudge's original lever was not adopted for a hundred years; its widespread use in Swiss watchmaking begins only in the mid-19th century, which is why it is called the Swiss lever despite being an English invention.
The co-axial escapement, invented by George Daniels in 1974 and patented in 1980, is the only commercially viable alternative to the Swiss lever in 250 years. It uses radial rather than sliding impulses, reducing friction and the need for lubrication at the escapement. Daniels licensed the patent to Omega in 1999, and Omega has used it in the Cal. 2500 (2000), Cal. 8500 (2007), and the modern Master Chronometer Cal. 8900/9900 series. The Omega Cal. 321 remains the only commercially produced watch movement alternative to the Swiss lever outside Omega itself.
Exotic escapements include the natural escapement (Breguet c.1790, used today by Parmigiani Fleurier), which eliminates lubrication entirely by using direct-impulse geometry; the detent escapement used historically in marine chronometers for high accuracy; and the grasshopper escapement (John Harrison, c.1722) that enabled the first successful marine chronometer. Silicon escapements, introduced by Patek Philippe, Ulysse Nardin, and Rolex in the 2000s, use silicon escape wheels and lever pallets for reduced mass, magnetic immunity, and tighter tolerances. Roughly 99 percent of mechanical wristwatches made today, by volume, still use a variant of Mudge's 1755 Swiss lever.
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