Stories / May 2019

HOW SELF-WINDING WATCHES WORK

The self-winding watch is the epitome of sustainable: renewable energy on tap (so long as you move your ass). Here’s how the magic happens…

The basic concept of an automatic watch movement is quite simply explained. When the wearer moves their arm, a rotor is spurred into motion, sending kinetic energy via a series of gears to the mainspring (a spring that, when tightly coiled by winding, then gradually unwinds, powering the watch’s movement). It’s a neat example of ‘clean energy’, harnessing the wearer’s motions and turning them into power. If only every machine could be fuelled so sustainably…

Most experts agree that the earliest authentic automatic movements were housed in pocket watches created by 18th-century watchmaker Abraham-Louis Perrelet of Le Locle, Switzerland. In 1777, Perrelet designed and built a self-winding mechanism for pocket watches using a pedometer-like oscillating weight, moving up and down. Many other leading watchmakers of the day, including another Abraham-Louis (the legendary Monsieur Breguet), worked on solutions for converting motion to stored energy in a watch, but their complexity made them difficult and expensive to produce, and it wasn’t until the early 20th century that automatic movements began to grow in popularity.

Among the earliest commercially successful self-winding watches were those produced by English watchmaker John Harwood in the 1920s. Harwood patented a bumper rotor system, using a pivoting weight which swung in a back-and-forth motion as the wearer moved, rotating through part of a circle (roughly 180-200°), causing the mainspring to coil. This variant of self-winding mechanism enjoyed just a few decades’ popularity and was used in many early-model mid-century Omega Seamasters.

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